Question: Can I use a PC-133 memory as a 66MHz memory?

[JYA]

Can I use a PC-133 memory as a 66mhz memory in a Pentium pro system? I plan to upgrade my computer in three months, and I can still use the memory in my new system.

Im using a Diamond W6-LI MBO, it supports EDO DRAM and FPM DRAM.

Thanks

 

[ElFenix]

if you've got a pentium pro that will take 168 pin DIMM sdram, such as one running on a 440LX chipset (they made slockets for those too!) then yes. if you've got a 440FX chipset, then probably not. it will only take 72 pin SIMM edo dram. or fpm dram. but it won't take the modern DIMM.

 

[BearX00]

definately, memory is "backward compatable" so to speak. The rated clock speed is basically a maximum, so runnning it slower wont give you any problems.
Although you might want to make sure all your ram has the same nanosecond rating, that possibly could screw things up but im not sure.

 

[Doggiedog]

It's not 100% true that memory is backwards compatible.

I had a PC66 440LX MB and added PC100 SDRAM to it and it didn't work with any of the three sticks I used.

I think it really depends on your MB.

 

[Oyeve]

I dont see why not. I installed a 128meg stick of 133mhz memory in an old pentium 166mhz mmx pc with a VIA 82c595 chipset and it runs just fine. I dont know about the old intel chipsets but the old VIAs work fine.

 

[BearX00]

it could be mobo dependant. In my old system that had an Abit bh6, i have PC133 memory running at 66Mhz ( i know its a waste) and it runs just fine.

 

[AngelOfDeath]

Yes, but why would you wanna do that???. You do ofcourse have to make sure that it supports SDRAM. My friend has a mobo which only supports 168pin EDO DIMM modules.

AoD

 

[Oyeve]

True Angelofdeath. I also have a PPRO system that uses 168 pin mem BUT it only uses 5 volt EDO DIMS and the "notch" is a tiny bit off so you cant even fit sdram into the slot or vice versa for that matter.

 

[ruckb]

Hi JYA,

you wrote, that your mobo supports EDO and FPM DRAM. So it seems, that you can not use SDRAM in your old System (not even "PC66" SDRAM).

Many comments where about the backward compatibility of SDRAM. Normally it should be possible to use PC133 SDRAM in a PC 66 SDRAM system. The basic functionallity is the same. But there are some small details, that can cause problems.
E. g. for a PC133 System the data is faster available after the clock. Therefore the old data of the last cycle is not as long valid as for a PC66 SDRAM. So if the controller is taking the data very late it can happen, that it gets already the data of the next cycle. In this case it depends how well designed the system is, if it works or not!

ruckb

 

[Remnant2]

Also guys, be more careful in telling him that it'll work!

He explicitly stated that the MB says it supports "EDO DRAM and FPM DRAM". *not* sdram. In this case PC133 or PC66, neither will work in his machine.

Sorry, if that's the case you're pretty much out of luck, EDO stopped being compatible with new motherboards quite a while ago.

 

[JYA]

I finally made my mind, I will spend $70 plus shipping to get a 128mb 66mhz DIMM for my old Dual Pentium Pro system. Since it works smoothly without any problem, I think it deserves the extra Money.

Thanks