Old Socket 7 question...

[scorch2000]

Hi. I have an old ALI Socket 7 mb w/ a Pentium 200MMX CPU. The board accepts PC66 Ram and I want to put an additional 128mb in that system. My question is, can I use PC100 or 133 ram?? PC66 is hard to find and is expensive. Will it run properly?? Thanks!!

 

[Frenchie]

pc-100 and pc-133 ram is backward compatible with pc-66.

 

[Peter]

... there are limits - not in the PCxxx speed grade (SDRAM doesn't care about being run slower than expected), but in the SDRAM chip integration density.

Some older chipsets can't use the latest SDRAM chips to their full capacity - and some mainboards with chipsets that could are hindered by an old BIOS that doesn't set them up right.

Buy a double-sided 16-chip 128-MByte SDRAM, make sure you can return it should it not work in your system, and then go ahead and try it. If your system sees the full 128 MBytes, then it's good.

After that, use memtest86 to verify you got a good DIMM.

Regards, Peter

 

[Pederv]

What Peter is saying is, your board might not take 128MB sticks only 64MB sticks.
Check for a bios upgrade also.

 

[SpongeBob]

Yeah pederv has the right idea, i know super socket 7's(most at least) take 128mb modules, but if it is only a socket 7 the largest it can probably take is a 64.

 

[Peter]

Actually, the limit is in size-per-row.

So if the board can take a single-sided 8-chip 64-MByte stick, then a double-sided 16-chip 128-MByte one will work equally well. Same SDRAM chip technology, only two rows instead of one.

Newer 128-MByte sticks are single-sided 8-chip however, and these use higher integration SDRAM chips that may or may not work on an older chipset.

Anyway, later non-super socket-7 chipsets can handle the latter too - SiS 5581 through 5598 aka TXpro-II, ALi Aladdin IV aka TXpro, VIA VPX aka VXpro+ as well as VP2 and VP3, Intel TX, all fine, provided BIOS is intelligent enough to detect those large chips correctly.

Really poor SDRAM support is in the first generation SDRAM chipsets: Intel VX, VIA VP-1 aka VXpro, and SiS 5571. These are limited to 16 MBits per SDRAM chip, 32 MBytes per (double-sided 16-chip) DIMM stick.

Regards, Peter

 

[Priit]

Thanks, Peter, that information really helped me to clear things out why I couldn't get SDRAM modules working properly on my VX-baset old Tyan mobo. I tried with 16,32,64 and 128Mb modules, only one that worked were double-sided 32Mb DIMM's. There may also be problem with older socket7 when they want to run SDRAM on 5V like SIMMs. BTW, my friend has P2/300 with QDI EX-chipset based mobo and that doesn't "eat" any other DIMMs I've tried that those dual-sided 32Mb ones, too.
Bios update needed ?