question about RAM differences

**snuggans** · October 18, 2006, 02:23 PM

if i put 1 GB of DDR2 PC5600 667 RAM on my computer, and then i add 1 GB of DDR SDRAM PC2700 166 RAM, will there be any problems? also, how will it perform?

**communisto** · October 18, 2006, 02:33 PM

answer, it wont work at all, ddr2 and ddr have different slots, so they cant even be in the same system

**Shaun** · October 18, 2006, 02:38 PM

Originally Posted by WaynehMarls

if i put 1 GB of DDR2 PC5600 667 RAM on my computer, and then i add 1 GB of DDR SDRAM PC2700 166 RAM, will there be any problems? also, how will it perform?

Short answer, it wont work. Both sticks need to be the same. If you do buy more DDR2 RAM, then make sure its as fast, and only as fast, as your slowest stick, otherwise it will only run as fast as your slowest stick.

**Ahiga** · October 18, 2006, 02:40 PM

So you can't have conflicting RAM sticks? At first you say it wont work then you say it can only run as fast as your slowest stick.

**Shaun** · October 18, 2006, 02:46 PM

Originally Posted by Ahiga

So you can't have conflicting RAM sticks? At first you say it wont work then you say it can only run as fast as your slowest stick.

Correct, you cant have two conflicting sticks, but two DDR or DDR2 sticks arent conflicting, and I meant that if you get two non conflicintg sticks they will only run as fast as the slowest one.

**Lee1026** · October 18, 2006, 02:50 PM

if i put 1 GB of DDR2 PC5600 667 RAM on my computer, and then i add 1 GB of DDR SDRAM PC2700 166 RAM, will there be any problems? also, how will it perform?

Short answer: no, it won't work.
Long answer: No, it is practically impossible to get it to work.
Very long answer: It could work theorically if you are capable of making your own chipset that can control DDR1 and DDR2 at the same time at decent speeds. And then you would need to have you own modded OS that would know when to something in fast ram and when to put something into slow ram. And then you will have to mod the motherboard to put in DDR1 slots. And then you have to mod the voltage controls to give them the right voltage. And then you would have to modify the bios to deal with this rather strange set-up. If you are capable of doing all that, then yeah, it would work and it would give you some nice performance just like if you had 2 gigs.

**vikrant** · October 18, 2006, 03:37 PM

i have got two 512 ddr 2's now
i with 265 mhz
and one with 400 mhz
so does it mean my net speed will be 265 mhz ??

**Erik** · October 18, 2006, 03:46 PM

Originally Posted by WaynehMarls

if i put 1 GB of DDR2 PC5600 667 RAM on my computer, and then i add 1 GB of DDR SDRAM PC2700 166 RAM, will there be any problems? also, how will it perform?

Like communisto said: you can't do that.
DDR2 doesn't physically fit into a DDR slot and vice-versa.

Originally Posted by vikrant1986

i have got two 512 ddr 2's now
i with 265 mhz
and one with 400 mhz
so does it mean my net speed will be 265 mhz ??

Not necessarily.
You can set the RAM speed manually in the BIOS.

You might be able to squeeze more than 266mhz out if a 266 rated memory module.
All the "266" says is that it's guaranteed to work at that clock speed but you can usually overclock RAM pretty far.

But all RAM modules must work at the same speed, you can't set one higher than the other.
So the slowest module will determan your maximum (overclocking) speed.

One thing you have to watch out for:
Some higher clocked modules have slower access time.
So installing a 400mhz module might force you to reduce CAS/RAS latencies.
And again you don't have individual settings, so the slowest module determans the latencies of the entire system.

This is what happened when I foolishly bought a 400mhz module to go with my 333mhz system (they were out of 333 at the moment, and I didn't want to go back): it increased latencies a lot, making my existing memory actually slower than it was before.