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SDRAM speed considerations

1246 Views 13 Replies 8 Participants Last post by  Battousai
My motherboard (VIA KT133) manual says it supports PC-100 and PC-133 types of SDRAM. Currently, I have two 32MB PC-100 SIMMs installed, and the third socket is free. Yesterday, I finally bought a 128MB SIMM, only this time it's PC-133. The store owner told me that I can use this alongside my two PC-100 SIMMs. I never believed him but I still tried it when I got back home. Well, it didn't work. The PC just beeps and beeps, indicating (from experience) that it's not detecting any RAM. So I had no choice but to remove the 32MB SIMMs and use just the 128MB one.

The question is: is the storeowner really stupid, or am I doing something wrong? Are there some BIOS settings that I should change so that my three SIMMS would work together (even if it means downgrading my PC-133 to PC-100)? Thanks...
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Dont think so , sometimes sticks wont work together.
Why not just ditch your pc100 stuff and get some more 133.
I bought 256mb for £18 today so its not like it's expensive.
Unless did u go in your bios and set the ram as host clock + pci clock?If so then your 100 is trying to run at 133 and wont work if not do it or I dont think your 133 will be running at 133.
Maybe your bios detects the ram at 133 and sets to run at 133 so making your 100 try to run at 133 which it obviouslly cant , try going in and setting to just host clock then maybe the 100 stuff will work.....
but what do I know :eyes:
Onejaz is correct.. YOu can't run pc100 sdram dimms at 133.. So essentially, your trying to oc your pc100 to 133mhz.. YOur pc133 can run at both 100mhz and 133mhz.. Do what onejaz suggested and run your ram at 100mhz.. But you won't be getting the best performance from your pc133.. Get some more pc133 sdram.. They are about 18 bucks for one 128meg stick.. I myself ordered some OCZ ice pc150 sdram 512meg.. Gonna get it on monday.. These can run up to 150 mhz and higher..
your lucky!!!!!!! you know why?
coz my classmate try that and his motherboard been damage he put a two 32MB and 64MB memory and when he boot or i should say it never boot

the next thind is..... i found him in a computer shop buying a new mobo
sorry guys your all nuts.

a lot of pc100 ram will do 133. anyways he's running at 100 fsb so no problems.

count the number of black boxes on one side of the ram sticks. if its an even then its ecc and if its an odd number its non pariety ram or the other way arround. i forget. ecc and non pariety ram will not work together.

i'm guessing the old ram is ecc and the new ram is non pariety. i believe non pariety is cheaper to make. it also runs about 3% faster.

and FireGl your classmate must be retarded because its not going to kill your motherboard. the computer will boot or not and then it will start beeping to indicate a ram problem.
ebola: lol, black boxes? :D :p (sorry just sounded funny no pun intended).. iirc, even = non-parity and odd = parity.. the extra chip on the parity ram is for the parity bit..
The FSB isn't always what the ram is running at in some Mobos.. I have a via kt7133a mobo running the FSB at 100mhz(200mhz ddr) but my ram is running at 133 mhz.. I think he needs to set something in his mobo's bios..

By the way.. what is your system specs, Battousai?
actually, it's because PC100 and PC133 are different standards for mainboard technology....

so... they are incompatible, why don't you try to get all your stuff from the same standard? because you cannot mix them...

*hey... I'm back!!!

edit: what I said is AFAIK, so if that wrong correct me plz
did you leave the board????

Lol*** :D :D :D :D :D :D
Originally posted by takmadeus
actually, it's because PC100 and PC133 are different standards for mainboard technology....

your completely wrong. it doesnt matter. hehe. sorry im sounding a bit mean tonight.

i think your thinking about the bx chipset vs the i800 series chipset. bx was intended for pc100 but the new and much worse i800 series motherboards were made for the p3 eb (133) chips.

and then abit came out with the bx 133 raid and said heck with that, lets make a pc133 based bx board, since bx is better than the other crap intel chipsets.

seriously it doesnt matter. the only conflicts are between parity and non parity ram. untill you get to ddr registered ram but thats another story.

and Xeven, its easiest to explain parts by what they look like to people who have no clue.

yea it did sound kind of funny
Thanks for all the replies!

fivefeet8: Yeah, that's exactly what I'm trying to do: set the BIOS to make the 3 SIMMS run at 100 MHz, but I still don't know which settings to change (if it's indeed possible).

I guess you're right about my PC-133 stick not being able to run at its best while running at 100 MHz with the 2 32MB sticks, but I'm guessing that 192MB (128 + 32 + 32) at 100MHz is better than 128 MB at 133 MHz, that's why I wanna use the two old SIMMs.

Dithch the two PC 100s, huh? So... does anybody want to buy them? :D

BTW, I've got AMD Athlon 800, Via KT133 chipset-based mobo, and 128 MB SDRAM (PC-133).
Originally posted by Battousai
Thanks for all the replies!

fivefeet8: Yeah, that's exactly what I'm trying to do: set the BIOS to make the 3 SIMMS run at 100 MHz, but I still don't know which settings to change (if it's indeed possible).

Well.. On my abit kt7a raid mobo.. In the bios there are some options to set the FSB and Pci mhz.. Then there is a ram option to set it to just FSB or FSB+pci.. My ram is set to FSB+pci since I have 133mhz ram sticks.. So either the ram runs at the FSB speed: 100mhz, or the ram runs at the FSB speed plus the pci speed.. 100+33 = 133mhz for ram.. PCI runs at 33 mhz.. Check if your bios has some settings similar to those..
Battousai, just a small correction: PC100 or PC133 are DIMM modules not SIMM. SIMM(Single In-line Memory Module) are very old and are no longer being used in today's computers. DIMM=Dual In-line Memory Module.
Zephon: I see. I'm pretty sure I've read somewhere (a long time ago) that DIMMs would work on your PC only if they come in pairs, thus the "dual" term as opposed "single." So I referred to my sticks as SIMMs since they could work alone. Oh well, who am I to argue, anyway?

I've found this setting in my BIOS, "SDRAM timing by SPD (speed)" and I've changed it 100MHz, and my two sticks were detected, the 128MB one and a 32MB. I've checked the other 32MB stick, but I think it got damaged along the way so I didn't use it anymore. So now I have a total of 160MB at 100MHz.

Then I've tried using Norton Utilities' System Information Benchmark. My PC turned in a rating about 7 points lower with 160MB (100 MHz) installed than when I had just the 128 stick at 133 MHz. So I guess I should stick to 128MB at 133 MHz, huh?
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