Server Memory — 40 Frequently Asked Questions
Real questions enterprise IT engineers ask about Server Memory, with practical answers from Pro Disk Engineering. Questions sourced from Server Fault and Network Engineering Stack Exchange under CC BY-SA — see source links per question. Answers are original Pro Disk Network content with links to our buying guides and product catalog.
What does Virtual memory size in top mean?
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (180 votes · 394,562 views) ›
Meaning of the buffers/cache line in the output of free
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (208 votes · 299,376 views) ›
Any benefit or detriment from removing a pagefile on an 8 GB RAM machine?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (222 votes · 84,543 views) ›
Dump a linux process's memory to file
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (89 votes · 252,686 views) ›
Get a history of CPU/memory usage
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (49 votes · 312,224 views) ›
How does vm.overcommit_memory work?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (92 votes · 196,129 views) ›
DIMMs: Single vs. Double vs. Quad Rank
Server memory questions usually come down to rank, density, and channel population.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (60 votes · 228,025 views) ›
Caching/preloading files on Linux into RAM
Server memory questions usually come down to rank, density, and channel population.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (104 votes · 99,760 views) ›
How to read memory usage in htop?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (73 votes · 151,504 views) ›
Why drop caches in Linux?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (96 votes · 89,752 views) ›
Difference between 2Rx4 vs 2Rx8 RAM
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (40 votes · 182,552 views) ›
In Linux, what is the difference between "buffers" and "cache" reported by the free command?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (80 votes · 79,479 views) ›
How to find memory usage of individual Windows services?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (45 votes · 117,571 views) ›
Linux: how to explicitly unswap everything possible?
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (73 votes · 34,429 views) ›
How to limit the memory used by an application in IIS?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (27 votes · 111,293 views) ›
How to understand the memory usage and load average in linux server
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
HBA firmware mode: IT-mode (pass-through) is required for software RAID (ZFS, vSAN, Ceph). RAID-mode for hardware RAID. LSI/Broadcom 9300/9400/9500 series HBAs flash between modes cleanly.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (60 votes · 44,977 views) ›
How do I get notified of ECC errors in Linux?
Server memory questions usually come down to rank, density, and channel population.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
BMC access: ipmitool -H <ip> -U admin -P <pw> chassis status for remote IPMI. For Dell iDRAC, HPE iLO, Lenovo IMM/XCC, Supermicro IPMI — all expose Redfish REST API as the modern alternative.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (44 votes · 58,921 views) ›
Does memtest86+ test memory which is used to run itself?
Server memory questions usually come down to rank, density, and channel population.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (65 votes · 6,602 views) ›
vSphere education - What are the downsides of configuring VMs with *too* much RAM?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (57 votes · 10,303 views) ›
Something eats all memory (I suspect memory leak on some app). How to detect what?
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (17 votes · 87,247 views) ›
Virtual Machine memory usage not appearing in TaskManager
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (41 votes · 34,366 views) ›
How to check if RAM is running in ECC mode?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (21 votes · 58,044 views) ›
Would you use ECC RAM in a workstation?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (28 votes · 43,767 views) ›
What is ECC ram and why is it better?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (31 votes · 29,160 views) ›
Should I be concerned that swap is being used on a host with nearly 40GB of free memory?
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (40 votes · 11,138 views) ›
Should I use bios "Advanced ECC" in Dell PowerEdge R710 Bios with ECC DIMMs?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (16 votes · 43,559 views) ›
Non-ECC memory with ZFS: a stupid idea?
Server memory questions usually come down to rank, density, and channel population.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (21 votes · 16,459 views) ›
What is nonpaged pool?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (6 votes · 39,590 views) ›
What is the Rowhammer DRAM bug and how should I treat it?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (21 votes · 1,784 views) ›
What RAM options do I need to know before buying Server RAM?
Server memory questions usually come down to rank, density, and channel population.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (19 votes · 5,292 views) ›
How to use kdump/crash to investigate an OOM issue?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (13 votes · 13,971 views) ›
Where's my memory?! Nginx + PHP-FPM front end webserver slows to a crawl
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (8 votes · 17,847 views) ›
The importance of ECC memory
Server memory questions usually come down to rank, density, and channel population.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (13 votes · 5,173 views) ›
WmiPrvSE memory leak on Windows 2008 *R2*
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (11 votes · 6,516 views) ›
Baffling Memory leak. What is using ~10GB of memory on this system?
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (11 votes · 6,159 views) ›
What does ECC RAM failure look like
Server memory questions usually come down to rank, density, and channel population.
DIMM type rule: RDIMM and LRDIMM cannot be mixed in the same channel. UDIMMs do not work in server motherboards. ECC and non-ECC cannot be mixed. Match rank and density across all DIMMs in the same channel.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (10 votes · 6,903 views) ›
Loads of memory in "standby" on Windows Server 2008 R2
Server memory questions usually come down to rank, density, and channel population.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (6 votes · 14,046 views) ›
How to limit memory usage by application in linux?
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (6 votes · 10,608 views) ›
How to force ECC error
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
Original question on Server Fault (10 votes · 1,788 views) ›
Windows 2012 Core Extreme memory use on SVCHOST/Workstation service
Server memory questions usually come down to rank, density, and channel population.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships DDR4 / DDR5 RDIMMs and LRDIMMs from Crucial, Kingston, Samsung, Micron. Memory buying guide · Memory catalog
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