Would DDR 400 ram , work on a computer with DDR 333?

Question

Hi,

Ive been reading the net alot. and some sites mention (while some sites say it is not true) that DDR 400 is backwards compatible with DDR333 (my brother wants to upgrade his ram, and he has a DDR333 chip in his computer already).

Anyways, id like to know if it is backward compatible, because where I live, DDR400 is cheaper than DDR333.. so id rather get the cheaper option.

Also, will there be better or worse performance compared to running two DDR333 chips?

Lastly, Is it ok to run CL 2.5 Ram with CL 3 Ram?


Thank you so much!

Answer 1

yes, you can run a DDR400 with a DDR333 in the same PC. the DDR400 will not be downclocked, it will simply run the same speed as the DDR333.

concerning the CL:
CL means CAS Latency (CAS = Column Address Strobe) and is calculated for the highest possible Bus Speed (FSB). a DDR400 runs with CL3 on a 400MHz FSB, but on a 333MHz FSB it runs also with CL2.5

Answer 2

If the physical sockets for the ram chips aren't different. Then yes DDR 400 will work in a socket designed for DDR 333. It will operate like a DDR 333 rather than DDR 400 if you do that. Note, you shouldn't place DDR 333 in DDR 400 sockets, you'll overclock and possibly fry a DDR 333 if you place it in the a socket that uses DDR 400 without slowing the clock rate down. Having more RAM doesn't hurt you, but the fastest part of your computer will be the slowest part which ends up being the system clock rate and the hard drive.

More ram allows you to run more programs without retrieving the data from the hard drive, which will be your slowest bottle neck. How ever, if your ram isn't running as fast as it could and you have a slow hard drive, that adds more to your performance decrease. So, add more ram, makes less need to talk to the hard drive, but If you get a faster drive, it will overall improve your performance along with more ram. CL 2.5 and CL3? well, I've done it on other computers, but if you want better and consistent performance , stick with keeping the memory the same. Some motherboards won't boot unless the memory is all the same

Answer 3

DDR memory is designed to be backward compatible. If your computer came with a 128 MB module, you can add 256 MB.
Anyways, you can add faster memory to your computer yes. The DDR333 can upgrade to the DDR400, but make sure your
processor is up to date as well. As for the CL2.5 Ram with the CL 3 Ram, I would worry about overclocking, depending upon the chipset you are using. Check out Crucial.com

Answer 4

You CAN run DDR400 on a DDR333 board, but it will only run at the slower DDR333 speed. As far as I know, it will be the same as having a DDR333 chip in place. Not sure about CL2.5 with CL3.

Answer 5

First. Yes, it is backward compatible. Second, it will only run at the speed of the slowest memory installed in the system. Meaning it will not degrade the performance, just that you will not see any gains from it unless you replace all of it with 400. This will be the same for e CL also.

Answer 6

The mother board should downlock the ram, it might cause some problems, so keep the information to return it if messes up, but all in all it should be downclocked to 333 and work fine.

Answer 7

Yes it should work fine. The 333 is simply the ammount of memeory. The DDR is the type. As long as it's teh same type it should be fine.

Answer 8

yes it will worc but will orc at 333 not at 400 as all the ram should work at same speed

Answer 9

yes, this is very compatible..see because 333 is jsut memory so it just adds to it :)