Win 7 Professional 64bit memory support

Alex Calvo

Mar 27, 2013
Hello folks, I have a freshly built everything new MSI A75A-G55 motherboard w/ an AMD A8-3870K CPU in it 32GBs of Corsair DDR3 1,600mhz XMS3 memory. When I placed just 8GBs, one dimm, in the MB I installed and ran Windows 7 64bit Professional and there was 8GBs of memory with 7.49 available, 1/2GB for the OS I guess. Then I added an additional 8GB dimm and it brought the memory to 16GB with 15.5 available I did all the appropriate Windows Updates etc. I had installed Google Chrome and Mozilla Waterfox browsers that was all then I added an additional 16GBs of memory bringing the total to 32GBs of ram. All the memory is present an accounted for in the BIOS which is a brand new BIOS as well. When i booted the computer this morning it states that only 16GBs of memory is available yesterday it said there was only 15.5 available. Does any one have an answer to why this is occurring this way? Professional should recognize 192GBs of memory. Thank You, Alex


What speed is your memory set to in the BIOS? If 1600, or higher, try dropping back to 1333 (be sure to save) and reboot the system. Sometimes systems have trouble operating at higher memory speeds with all memory slots populated. The performance difference between 1333 and 1600 will be negligible.

Also, if you are using the integrated video (a.k.a. APU), that will take some of your memory and could explain the 15.5 of 16GB available reading.