Two months ago I upgraded my old 256MB DDR333 to a Kingmax 512MB DDR400. I installed the new RAM with no problems. Last week, I noticed that my PC had slowed down considerably. Upon checking, I saw that only half of my 512MB RAM was registering (both in WinXP and in the BIOS). Thinking that the RAM had fried, I returned it to the store where I bought it to have it replaced. When they tested it, lo and behold, the RAM registered correctly on their system. I decided to test it independently on a friend's PC, and sure enough, the RAM was being recognized correctly on his system as well. I then borrowed his 512MB DDR400 RAM and installed it on mine, and my PC recognized the size correctly, i.e. 512MB. When I tried to test the Kingmax RAM again on my PC, only 256MB was registering. I have not installed any new hardware or software recently, and have been having no other problems with my PC. So my question is, what the hell is going on? Oh, by the way, my old 256MB DDR333 works fine.

Here are my specs:
Gigabyte 8IPE1000 Rev 2.x Motherboard
AWARD BIOS FI (Latest BIOS Flash updated)
Intel PIV 2.60Ghz (Dual Processors running)
512MB DDR400 RAM (supposedly)
2 Samsung 80GB HD
2 CD-ROM Drives (1 CD-RW)
Floppy Drive
250 watts PSU

Any help, suggestions, comments will be greatly appreciated. TIA!

"Bend the wind."

"250 watts PSU"

Flirting with disaster with just a 250W PSU.

Try cleaning the contacts on both your RAM & the DIMM slot(s)

for the 5,000 post, go to
www.crucial.com
run the memory scan to see which ram that board can use.

@jam

"Try cleaning the contacts on both your RAM & the DIMM slot(s)"

Been there, done that, no change.

"Flirting with disaster with just a 250W PSU."

You're right about that, planning to have it replaced right away, esp. since I have multiple drives. Could that be the cause of the RAM being read wrong?

"Bend the wind."

@mountain

Already visited crucial.com, even consulted the motherboard manual, and confirmed the DDR400 512MB RAM is indeed compatible with the board (max allowed is 1GB per slot, 4GB total). And I used that RAM for two months before it gave out.

"Bend the wind."

Have you tried each stick one at a time in first postition?

DerekW

"Could that be the cause of the RAM being read wrong?"

I doubt it, but it would be worth a check. Try temporarily lightening the load on the PSU...unplug the floppy, optical drives, & the 2nd HDD, then see if the full 512MB is recognized.

@derek

Yup, tried that too, on all 4 slots. My friend's 512MB DDR400 RAM works, mine doesn't. My old DDR333 works, too, on all 4 slots. Am totally confused as to why that is, especially since the problematic RAM works on other PCs. If it was totally defective, then the PC wouldn't boot, but it does, only it shows up at half its capacity, i.e. 256MB.

"Bend the wind."

@jam

Nope, RAM still only showing up at half-capacity, even without the extra load.

"Bend the wind."

Maybe it is a double sided/single sided issue and the RAM is not correct for your particular machine.

DerekW

@derek

But if it is a single-sided/double-sided issue, wouldn't it have shown up/acted up immediately after I first installed it two months ago, not just now? Besides, my friend's RAM is double-sided, similar to mine, and his RAM is being recognized correctly, as was mine for two months (well, until last week anyway).

"Bend the wind."

I had this exact same issue years ago, I just give up on the M/board in the end as it would have 512mb 1 week and 256 another it was an Asrock board. I would just face it and accept it's a compatibility issue. Change ram with shop or ask if you can swap it with your mates. As yours works with his & vice versa.

try running memtest http://www.memtest.org/

Before posting try google. Backup. Use anti virus software.

Re #10. Yep agreed now you've confirmed that it showed OK at the outset and took 2 months to happen.

The only things left, assuming you've cleaned the RAM edge connectors with a pencil eraser, appear to be a mobo problem (possible a bad joint near the RAM sockets), or the Power Supply.

This would be a most unusal symptom of PSU problems and would require the output voltages to be well below spec for anything of this sort to happen.

DerekW

I had this issue just the other day. After re-setting the CMOS (via mobo jumper), the full 1GB returned :s strange but true!

Yeah, #14 seems worth a shot.

I hadn't thought of that one and I don't think it is particularly strange or unlikely possibility.

DerekW

Re #14, will try that. Usually just reset the CMOS by removing the battery, but will it try it as per your suggestion, no harm in trying.

As for #13, planning to replace the PSU ASAP. I suspect it may have something to do with the problem, though remote the possibility may be. Need to have it replaced anyway, what with the load it's carrying. Will report back on the results ASAP.

"Bend the wind."

Reset the CMOS via jumper, no change.

Replaced the 250W PSU with 400W PSU, no change.

512MB DDR400 still only registers as 256MB. Bought two new 512MB DDR400 sticks, and they both work fine.

"Bend the wind."

Goodness knows, must have been something about it that didn't suit your machine.

DerekW

There's always something called the X factor.

No matter how much you try, you will find that sometimes the damn thing just wouldn't want to work. This happens to everything.

Cheaper mainboards or unpopular manufactures have more compatibility issues.

Gigabyte and ASRock are ... not the best things in the world.

386 WITH Math co-processor eat your heart out! 25 Mega Hertz
2 Mega Bytes of Random Access Memory
70 Mega Bytes of Hard Drive
Diamond ISA Video Card with 512 Kilobytes of Memory
2 x Caddy

Re #19 - All things considered, I think you're right. I've tried (almost) everything, so I think it boils down to a compatibility issue, which means there's nothing I can do about it but to give up. Thanks, everyone, for all your comments, suggestions, and advice.

"Bend the wind."

There are two situations when these symptoms occur. This commonly happens when the computer requires 2 clock SDRAM as opposed to 4 clock SDRAM. Computers that require 2 clock SDRAM usually have 133-233Mhz processors. 2 clock SDRAM is an older specification than 4 clock. The two are not interchangeable and cannot be mixed. (CAS latency issue)

This can also occur when PC100 memory is installed in a computer which requires PC66 SDRAM.