2 RAM Questions

I have a T61 (lenovo) with a Intel T7300 processor.

Question 1:
I have 1Gb of DDR2 667mhz RAM installed. I also have another 1GB stick of DDR2 800mhz RAM which I'm going to install this afternoon. Is it true that running these two sticks together will mean that the 800mhz stick will only run at 667mhz?

Question 2:
800mhz RAM is quite a bit more expensive than 667mhz. Especially if you're looking at 2GB sticks. For example, Newegg has OCZ 2GB DDR2 667mhz for about $110 whereas the OCZ 2GB DDR2 800mhz runs $143. Is the faster RAM worth it? Is it worth $33 bucks? Anyone have experience on this issue? Where can I read/see about some benchmarks? What would you recommend?

Thanks all!

 

no laptops can run 800mhz memory yet. the newest chipset only supports 667mhz. so even if you only had 1 800mhz stick of ram, it would run at 667mhz.

however, if you had a chipset that supported 800mhz ram, and you had 1 x 667mhz and 1 x 800 mhz modules, then, yes, the fast one would clock down to 667mhz.

so, no. its not worth any extra money because its not going to run any faster.

 

Q1: Yes, also make sure that it is 1x1gb stick installed rather than 2x512mb.

Q2: No, it is not worth it since Santa Rosa cannot support 800MHz. It will automatically clock down to 667MHz

 

That is correct, the 800MHz stick will only work at 667MHz if the other ram stick alongside it is only capable of 667MHz.

Something to note is that right now, no mainstream current laptop architectures can run 800MHz ram at 800MHz, the current cap is 667MHz. This makes 800MHz ram somewhat redundant right now however it will come into play in the future when newer systems become optimised for 800MHz and faster ram.

 

Thanks everyone.

I didn't know that current laptop architectures are capped at 667mhz! Glad I didn't waste my money!

 

Now I'm wondering:

Is it okay to use the 1GB stick of DDR2 800mhz RAM in my T61? Also, what's the difference between DDR2 667 (PC2 5300) and DDR2 667 (PC2 5400)? Which one is optimal for the T61 with an Intel T7300?

Thanks.

 

Yeah, DDR2 800 shuld work but it will downclock to DDR2 667.

Basically the PC2 5400 memories are tested to run at max 675MHz(338) which equates to a max bandwidth of 5400MB/s(hence PC5400). The PC2 5300 memories are tested to run at max 667MHz(333) which results in max bandwidth of 5336MB/s(hence PC5300). Ofcourse in real world there is no difference between these two since you will most likely be limited to DDR2 667 speeds by the chipset/FSB. Plus the extra 5Mhz even if it is usable doesnt make any noticable difference. Its all just marketing to lure unsuspecting buyers into buying 'faster' PC2 5400 memory at a higher price point.

Do remember to run Memtest86+ after installing any new RAM to make sure the new sticks are free of errors.

 

Thanks, miner.

one last question: what's the relationship between FSB and RAM Mhz?

 

FSB is the data tunnel which connects the cpu to the chipset and since all communication between the processor and the system has to pass through this, it becomes the limiting factor. If you want to know how it affects the memory speed that would require a long article dealing with the quad pumped bus, use of memory dividers, DDR...search the web for this topic and you should be able to find something which describes this in detail.

In your case though, you are limited by the chipset(memory controller) which supports memory up to DDR2 667 only.

 

Thanks again. no more questions ; )