Memory Failure

I did some overclocking (to 4.2 GHZ) and gave the CPU and memory a trial using Prime95 and other torture tests. Later, much later, I realised that part of my memory was gone!

Checking the BIOS showed memory failures of two of 8 modules, reducing my total to 24GB. I’m not sure it was the overclocking, the torture tests or simply old age (the PC and memory is 6 years old). The funny thing was that I could boot into Linux and run some applications, and whenever I used Firefox I would sooner or later get a freeze. I monitored the processes and saw that the kswapd demon was busy. It took me a little to grasp that I had “lost” memory.

My originally 32GB PC memory was divided as follows at boot:

  • 20GByte for Windows
  • 2GByte for hugepage tables etc. (that is a lot, but I wanted to be on the save side)
  • The rest (10GByte) for Linux

Since I allocated 22GByte to hugepages at boot, my Linux host had only 2GByte memory when 8GByte of RAM went bad.

Usually 2GByte would be enough for a Linux Mint Mate host, but having dozens of tabs in Firefox eventually exceeded the available memory. I had reduced my swappiness  value to a minimum, which was great with lots of memory. But 2GByte is a little low.

It’s difficult to find the same memory I bought 6 years ago, so instead of paying hundreds of dollars for replacing the entire PC memory, I decided to downsize to 24GByte altogether – 16GByte to Windows, around 1 GByte to hugepages page tables, and the rest to Linux. The system works fine and I believe I can use that PC for another 2 years for photo editing in a Windows VM, and general use under Linux.

Here is my basic configuration:

  • Intel i7 3930K CPU
  • Nvidia Quadro 2000 for the Linux host
  • Nvidia GTX 970 for the Windows VM
  • 24GByte RAM quad channel memory

Prime95 Benchmark: Linux Host versus Windows VM

This is yet another benchmark of my Windows 10 VM. This time I used the free Mersenne Prime Search software Prime95 (mprime under Linux) available at www.mersenne.org. I wanted to see if there is a significant difference between running the benchmark on the Linux host, versus the Windows virtual machine. Continue reading “Prime95 Benchmark: Linux Host versus Windows VM”

Virtualization Hardware Accessories

In my Running Windows 10 on Linux using KVM with VGA Passthrough tutorial I introduced different options for using the keyboard and mouse with the Linux host and the Windows VM. Running a virtualized Windows VM means running two separate systems – the Linux host and the Windows VM – both of which require input and output devices. Continue reading “Virtualization Hardware Accessories”

Keyboards and Mice

I’m the type of person who is learning things the hard way. This is also true for the purchase of computer equipment and peripherals. I cannot even recall how many times I have replaced my computer mouse and keyboard in the last decade.

One should think that a mouse or a computer keyboard aren’t exactly rocket science – well they aren’t! Yet many popular mice or keyboards are either bad by design, or fall to pieces within a relatively short time.

Below is a list of things you should be checking when purchasing a computer mouse or keyboard. It is based on my personal experience – your experiences may be different, though. Continue reading “Keyboards and Mice”