As far as I know they are both the same, V5.10 was just made to accommodate some of the newer chipsets, but a lot of people have had trouble with 5. If you use V5, when the test first starts it will tell you to push certain keys if you have a multi core CPU. Don't Push any keys, and the test will start in a few seconds. You will want to download either the ZIP file which contains an ISO filre that you have to burn to CD. You have to have an ISO burner to do it. Windows has an ISO burner that will work well Just double click the ISO and the Windows ISO Burner will open. If you want to run it from a USB Flash drive, download the Pre configured USB one. Put in a USB flash drive, after unzipping he file, open the program, tell it the drive letter of the USB Flash drive and click the Format check box and it will start and install it to the USB Flash drive. Whichever one you use, boot from it and the test will automatically start. Just let it run until you have done 8 complete passes at a minimum, more is better, or as Icit2LoL showed until you get an error. If you get an error, your ram has failed so there is no reason to continue. To stop the test, just push the Escape key.