Windows 7: 8gb ddr3 windows 7 ulitmate x64 3.87 usable

i am running
AMD QUAD CORE FX-4170 4200MHz Bulldozer
8GB DDR3 memory (2 x 4GB 1333MHz)
ASUS M5A78L-M/USB3 Motherboard
680W G7 Power Extreme ATX PSU
ASUS NVIDIA GeForce GT610 2GB Graphics Card

Anyway my problem is that in windows 7 under system, sometimes it will say i can only use 3.87gb out of 8gb memory i have also noticed that in my bios it does not always register 8gb but in windows it will. I no my board can support this memory because it can support up to 16gb so why in the bios does it not always register 8gb and why in windows does it not always let me use the full 8gb thanks (:

Try removing the memory boards from the motherboard, clean the sockets with a blast of compressed air, wipe clean the RAM contacts. Always make sure you touch a large metallic surface before you handle memory boards!!! This will prevent any static electricity damaging the memory. Now replace them back in memory sockets. Check in Bios whether the registered memory is 8GB or not. If it is not 8GB, try swapping the boards or change the sockets (if your motherboard has more than 2 memory sockets).

You can also try to reset the bios to defaults and check. Once the memory appears correctly in Bios then you can check in windows.

If windows still show usable memory is 3.87 GB, type msconfig in the command field inside start button and press enter whein msconfig.exe appears on the top of the start menu. The System Configuration dialog box will pop up.

In this dialog box go to Boot tab on top, and click on Advanced Options. In the Boot Advanced Options dialog box, remove the checkmark on Maximum memory setting. Click OK twice to close the MSCONFIG program. Reboot the system and check again.

Are you certain you are running the x64 version? We've had people before state that they were, with your same problem, and after a closer look, they weren't.

I've also seen the problem with integrated graphics using that memory.

im 100% sure its 64bit i checked plus if i wasnt using 64bit it wouldnt let me use the full 8gb some of the time (: and i have tried reseating the memory i have 4 memory sockets it is still doing the same thing i will try reseting the bios see if that makes any difference

I didn't notice it said 8gb. I thought you had 4. In that case, are they both 4gb modules? If so, then one could be faulty.

Enter 'resmon' in the start menu search box, hit enter.

In the 'Memory' tab, take a snip including the Processes section and post here.

For posting the information , enter 'Snipping tool' in the Start button > Search box, hit enter. Select the area you want to post and save to a convenient place.
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i have tried both sticks on there own and they appear to work fine aswell

The Hardware Reserved, 4GB, is for system resources and onboard graphics.
That is very high, if you don't need the onboard graphics go to your BIOS and you can disable it. That should give most of the 4GB back for other use.

it shouldnt be reserved should it because i put a graphics card in my self?