I just bought an A7N266-C mobo (nForce 415-D chipset) with an Athlon XP 1900 and 2 512 MB strips of Mushkin PC2100 DDR. My problem is that the system only recognizes them as 256 MB strips, so it boots up with 512 MB total. I have tested each DIMM by itself, and the mobo still only sees 256 MB each. It's really frustrating, I want my gig of ram!

Went to Asus's site, couldn't find any info. Same for nVidia's site. Checked the manual, but it's missing one very important part: no troubleshooting section! Anyone got any suggestions? Thanks!

Specs:
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Athlon XP 1900
Asus A7N266-C (nForce 415-D), bios 1001.E
1 GB Mushkin PC2100 DDR RAM
Enermax 431W Power Supply
Leadtek Geforce4 TI4400
nForce Audio (for now, will probably go back to SBLive)
WD 100GB Hard Drive

I'd make sure they show up as 512 in a different system. You could've been sold a pair of 256MB sticks by accident, or the sticks could be bad.

I believe that the Asus board requires nonECC registered Ram.

According to Mushkin there are three different modules of 512 Ram that is rated to work with the 415-D chipset:
512MB Hi Perf LEVEL 2 2100 222
512MB PC2100 DDR SDRAM SPECIAL
512MB High Perf PC2100 Mushkin CL2
Which is yours?

i haerd those chipsets are very particular about the ram you use.

Here's the specs off of Newegg.com (where I bought it from):

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DDRAM 512MB|64X64 PC-2100 MUSHKINAMD, VIA, ALI, SiS Approved, PC2100 = 266MHz FSB, Rated 2-3-3@133MHz, Uses 256-Megabit chips,64x64 Module, 32Mx8 Chip Density, Unbuffered & 6-Layer PC Board. OEM Model#: 990809 Special FedEx Saver Shipping $6.00
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It looks like I got the 512MB PC2100 DDR SDRAM SPECIAL (the picture on Mushkin's site looks just like my DIMM).

I highly doubt the DIMMS are ECC or registered, they weren't expensive enough. The manual does specifically say no ECC RAM, but says nothing about requiring registered RAM...

I agree. The OEM Model# is also the webpage product entry. You seem to have the 512MB PC2100 DDR SDRAM SPECIAL. In the small print on that page it does not mention the Nforce though its support page designates it as working with the Nforce.

On its Asus support page it refers to the ASUS A7N266-E (not C as in your mobo) http://www.mushkin.com/cgi-bin/Mushkin.f...880#asusa7n266e

Only the 512MB Hi Perf LEVEL 2 2100 222 actually refers to the Nforce in the small print and wouldn't you know it, it's 61 bucks more.

Well, I sent an email off to both Asus and Mushkin's tech support. Hopefully one of them will be able to help me out, though I'm not going to be holding my breath...

Very wise. Being on the cutting edge with the technology you are working with has little enough oxygen.

I am happy to say the problem has been resolved. After contacting Mushkin's tech support, I shipped the ram to them for testing. It turns out both dimms were improperly programmed, and when I got them back, they both showed up as 512 meg dimms like they were supposed to.

I gotta say I was extremely impressed with Mushkin's tech support, and I will likely buy their ram in the future. They always responded within a day of my emails, and, obviously, were able to fix my problem for me.