Mixing up DDR2s

[bidyut]

I know it's a little bit stretch, but I just wanted to ask this question.

 

I have Gigabyte P35-S3g motherboard. I have TWIN2X2048-8500C5D 2gb kit and it has been running fine. I think it runs at 800MHz speed because I didn't set the voltage to 2.1. So default it runs at 1.8v. The cas is 5-5-5-15.

 

Yesterday I bought TWIN2X4096-8500C5C 4gb module and added to the motherboard. On starting the computer, it keeps rebooting itself. The cas for this is 5-6-6-15. Should I return the memory module or I can tweak the bios make it run. I don't overclock or anything. Motherboard spec says it supports upto 8GB with 1.8v(4 banks).

 

Any help would be great in this regard.

 

Thanks

Bidyut

[RJLeong65]

I know it's a little bit stretch, but I just wanted to ask this question.

 

I have Gigabyte P35-S3g motherboard. I have TWIN2X2048-8500C5D 2gb kit and it has been running fine. I think it runs at 800MHz speed because I didn't set the voltage to 2.1. So default it runs at 1.8v. The cas is 5-5-5-15.

 

Yesterday I bought TWIN2X4096-8500C5C 4gb module and added to the motherboard. On starting the computer, it keeps rebooting itself. The cas for this is 5-6-6-15. Should I return the memory module or I can tweak the bios make it run. I don't overclock or anything. Motherboard spec says it supports upto 8GB with 1.8v(4 banks).

 

Any help would be great in this regard.

 

Thanks

Bidyut

 

The trouble is that you've now mixed two different kits with completely different ICs. All 1GB and 2GB DDR2 modules from Corsair are double-ranked - and the ICs used in the 2GB modules are of a much higher overall density than the ones used in the 1GB modules (1 Gigabit versus 512 Megabit). The mixed IC densities, in this case, caused the hiccups. The only way that a 2GB module can play nice with a 1GB module is if the 1GB module is single-ranked; unfortunately, none of Corsair's 1GB DDR2 modules at this speed meet this requirement.

 

In addition, with your processor you might have to lower the memory speed all the way down to DDR2-667 (the lowest memory speed that's officially supported in the P35 chipset's memory controller hub, or MCH) in order to run stably with all four memory slots filled. Socket LGA775 processors do not like memory to be run so far away from the true clock speed of their Front-Side Bus (FSB), especially with a full load of memory modules. And even DDR2-667 has a higher actual clock speed than an FSB1066 that's stock on the Q6600 (333MHz versus 266MHz).

[bidyut]

Thanks. That was a very clean and easily understandable reply.

 

Now is it worth downgrading to 667? Now days DDR2 memory cost way too high. Not worth throwing away the old ones and buying new ones! Running 2gb at 800 or running 6gb at 667; what is preferred in your opinion?

 

Thanks

[RJLeong65]

Thanks. That was a very clean and easily understandable reply.

 

Now is it worth downgrading to 667? Now days DDR2 memory cost way too high. Not worth throwing away the old ones and buying new ones! Running 2gb at 800 or running 6gb at 667; what is preferred in your opinion?

 

Thanks

 

Actually, I'd recommend replacing your 2GB kit with the newer 4GB kit and running 4GB at 800. With a Socket 775 platform there is hardly any difference in real-world performance between 5-5-5-15 and 5-6-6-18. On the other hand, with a newer i7 platform with DDR3 memory there is some tangible difference in real-world performance between 7-7-7-20 and 8-8-8-24.

 

Plus, DDR2 memory is right now relatively high in price because nearly all new systems now use DDR3 memory. Over the past few months DDR2 prices have gone up substantially while DDR3 prices have remained flat.

[bidyut]

Thanks for your help. I will do that.