I bet it is a compatibility issue with your motherboard.

It he RAM dual sided or single sided?

What is the exact brand and model number of the sticks?

What motherboard do you have?

Yep. If that's an ApolloPro133 (VT693A) chipset, it can handle max 128Mb RAM chips. The ApolloPro133A (VT694X) can do 256Mb chips. I suspect you have 256MB DIMMs with 8 chips. That means 256Mb per chip. If you have a VT693A chipset, only the first 128MB per chip will be used, so you get 256MB total...

A BIOS update might help, but it's not guaranteed.

Yeah I was going to suggest a BIOS upgrade as well. Had the same problem with an E-Machine with a Trigem Cognac motherboard which only saw 256 of the 512 mb it was supposed to be able to support. Only was to get it sorted was to upgrade the BIOS.

Hmm... bad on me then for not checking that out first.

The BIOS options do suck so maybe I'll do a flash update anyway and see if it helps. If it doesn't, at least I'll have more overclock options.

Gahhhrrrlic wrote:

Hmm... bad on me then for not checking that out first.

The BIOS options do suck so maybe I'll do a flash update anyway and see if it helps. If it doesn't, at least I'll have more overclock options.

You going to tell us exactly which board it is? And how many chips are on the DIMMs in question?

That will at least give an outline of what is possible, only if that all looks good is there much point in flashing the BIOS, at least for this issue.

dionb wrote:

Gahhhrrrlic wrote:

Hmm... bad on me then for not checking that out first.

The BIOS options do suck so maybe I'll do a flash update anyway and see if it helps. If it doesn't, at least I'll have more overclock options.

You going to tell us exactly which board it is? And how many chips are on the DIMMs in question?

That will at least give an outline of what is possible, only if that all looks good is there much point in flashing the BIOS, at least for this issue.

Sorry, I thought I mentioned that it was a VIA Apollo Pro 133 and the sticks have 8 ICs on them. Here's the exact page I bought: http://www.memoryx.com/aji.html

Via Apollo Pro 133 is the chipset, not the motherboard, and there's some confusion about it because Via's product page for the 133 contains pictures of the 133A (and neither page lists the relevant memory density info). Hence I want to double-check if it's a 133 or a 133A.

As for the RAM:

Chip - 8pcs 32x8

That's single sided with 256Mb (32x8) chips, just as I suspected. 256Mb is not supported by the Via Apollo Pro 133 (693A) chipset, it can do 128Mb max. If your board really has the 133 not the 133A, then you're not going to be able to use more than half of these DIMMs. For 256MB DIMMs with 693A (or indeed i440BX) you need to get ones with "16pcs 16x8", i.e. double-sided DIMMs with 128Mb chips.

If your board does have a Pro133A (694X) chipset it should be able to handle 256Mb chips in which case a BIOS update might help. But you need to identify the board before contemplating that...

dionb wrote:

Via Apollo Pro 133 is the chipset, not the motherboard, and there's some confusion about it because Via's product page for the 1 […]
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Via Apollo Pro 133 is the chipset, not the motherboard, and there's some confusion about it because Via's product page for the 133 contains pictures of the 133A (and neither page lists the relevant memory density info). Hence I want to double-check if it's a 133 or a 133A.

As for the RAM:

Chip - 8pcs 32x8

That's single sided with 256Mb (32x8) chips, just as I suspected. 256Mb is not supported by the Via Apollo Pro 133 (693A) chipset, it can do 128Mb max. If your board really has the 133 not the 133A, then you're not going to be able to use more than half of these DIMMs. For 256MB DIMMs with 693A (or indeed i440BX) you need to get ones with "16pcs 16x8", i.e. double-sided DIMMs with 128Mb chips.

If your board does have a Pro133A (694X) chipset it should be able to handle 256Mb chips in which case a BIOS update might help. But you need to identify the board before contemplating that...

No, I'm 100% sure it's the 133 without the A. The wiki page said it could support 1.5GB of RAM so I was deceived into thinking that 512MB would be fine. Of course I didn't ask the question about how the chips were configured. I guess these are what's known as "high density" chips? Even so, how can any of the memory be usable? How is the half it sees any different than the half it doesn't? I find it enigmatic.

"High density" is a totally subjective, time-dependent term. In 1998 128Mb chips were high-density. By 2000 they were low-density. Don't take this kind of shortcut, just stick to the density itself. Note that even manufacturers can give incorrect info. Intel claims the i430TX and i440LX chipsets can handle max 64Mb but in fact they are both perfectly capable of accessing 128Mb.

As for only half: it's a matter of addressing. If you have a street with 256 houses but can only use 128 house numbers, the other 128 don't get any post. That's what happening here.

dionb wrote:

"High density" is a totally subjective, time-dependent term. In 1998 128Mb chips were high-density. By 2000 they were low-density. Don't take this kind of shortcut, just stick to the density itself. Note that even manufacturers can give incorrect info. Intel claims the i430TX and i440LX chipsets can handle max 64Mb but in fact they are both perfectly capable of accessing 128Mb.

As for only half: it's a matter of addressing. If you have a street with 256 houses but can only use 128 house numbers, the other 128 don't get any post. That's what happening here.

Thanks for the explanation. Fortunately I went a bit overkill with the RAM, as I doubt it will bottleneck given the CPU speed and the limits that will impose on software. 256 should run just about everything and it's CL2 so I've already maxed everything out in the BIOS for timings - everything is happy.