I have purchased 2x4gb memory modules (total 8gbs) and have placed them in dual channel configuration on my Gigabyte motherboard.
I then noticed that Windows would detect 8gb installed (4gb usable) in system properties and 4gb hardware reserved in resource monitor.
I have searched the internet for possible causes. I know that the ram modules are fine, in fact I had this problem on my old 3x1gb modules but I didnt realise that 1 channel would be missing.
I have attached this image from my bios to show the problem:
As you can see, the bios detects the ram installed in the Slots but Enabled Slots only show 1 4gb module installed.
In CPU-Z, the dual channel configuration appears to be enabled, even though the BIOS only enables 1 slot:
I have also read that this problem can be caused by bent pins in the CPU socket. I have taken these images and circled the pins which appear slighltly bent. I just wanted some opinions before I touch them if these pins are indeed bent. Could this be the cause of my missing ram?
Which slots do you have the memory installed in? You will need to make sure that When enabling Dual Channel mode with two memory modules, be sure to install them in the DDR3_1 and DDR3_4 or DDR3_1 and DDR3_2 sockets. That is what you have right? -4 slots? It looks like you have them in DDR3_1 and DDR3_3. I know it's the basics but I figured it's a good place to start.
I don't see where the pins are bent to badly so I don't think that is the problem. I have seen and used some boards with bent pins - never in that area of the socket but they are barely bent and probably still making contact with the cpu so for the most part I don't think that is affecting anything.
My motherboard has 4 slots. I have tried installing them in the configurations suggested by the manual. I have swapped the mem modules around and the BIOS would decide to 'ignore' a different slot each time so I dont think a slot is faulty. In the BIOS, there are reports for Channel A, Channel B, Channel C. Depending on the configurations of the memory, a single Channel will not report anything back (tCL, tRCD, tRP etc). It will just be replaced by a '-'.
I have also tried to install my 2x4gb + 1x1gb memory modules together. I wouldnt mind if the motherboard would decide to ignore my 1 gb mem module but it will always ignore a single 4gb module. So I would have 5gb in total. In CPU-Z, it would report memory running in triple channel.
Given your reply and the fact that you have the same problem with the 3 X 1gb setup I would say one of the memory slots are bad. Most likely slot 1 since you tried them in slot 1 and 2 and also slot 1 and 4 and always came up with just 4 GB. Did you try putting the 1 gb stick in slot 1 and the 4's in slots 2 and 3? If slot 1 is bad I would think/hope that would ignore the 1 and give you 8. I do find it fishy that if you tried all those combinations and it always ignores a 4 stick that a memory slot is causing it though. But still, if you know beyond a doubt that both 4's work it doesn't leave much else than the mobo.
I think the problem is the mobo but not sure why. I have tried putting the 1gb stick in slot 1 but it would still use the 1gb mem and a single 4gb mem, ignoring the remainder 4gb mem module. I just wish it would decide to ignore my 1gb mem rather than the 4gb mem
However, CPU-Z and HWInfo shows this:
So it seems all slots are recognised by the system. Im not an expert but I think the problem is the BIOS, or one of the settings in the BIOS. As I understand, the BIOS send memory setup info to Windows. So if I can get the BIOS to use all slots, Windows should automatically be able to use the full ram.
The other thing is maybe you need to check your memory against the QVL for your board? Between that and gskill or corsairs memory configurators they will give you other choices. There is also the timings for your memory. If you go into bios and loosen the timings from 8 to 9 or 9 to 10, something along those lines, you might see a difference. What is the exact brand & model # of your memory?