I'm considering to upgrade mu CPU. Need advice

[Arclight]

Don't know if it's still relevant, but I pushed my system a bit to figure out the synced stuff:

CPU is now at 1600MHZ bus, with the memory at 800MHZ. CPU-Z reports ratio of 1:1, i.e. synced. Mystery solved.

[Castout]

Originally Posted by Arclight

Don't know if it's still relevant, but I pushed my system a bit to figure out the synced stuff:

CPU is now at 1600MHZ bus, with the memory at 800MHZ. CPU-Z reports ratio of 1:1, i.e. synced. Mystery solved.

Thanks. I'll keep that in mind. Doh there is this website which taught me about syncing by looking at the FSB alone......it even showed a table listing matched component of CPU and RAM. You could give them an email or perhaps I understand them wrong.

[Arclight]

I think it depends a lot on how recent that article is, and what they're comparing. This is with DDR2, I think with DDR3 you'ld need to run it at 1600MHZ: DDR3 at 1600MHZ effectively runs at the same bus speed (400MHZ) as DDR2 at 800MHZ effectively.

All this stuff changes and evolves so fast it's really difficult to keep the facts straight.

* No, that's not right. Argh, I don't know.

All I know is that My FSB is at 400MHZ, external bus for CPU is 1600MHZ and CPU frequency is 3.2GHZ. DDR2 frequency is 800MHZ and all utilities report a ratio of 1:1 (synced).

** http://icrontic.com/articles/core2_fsb_explained/2

To provide an example: Intel boasts that their Core 2s with a 266MHz FSB actually have a “1066MHz FSB!” It’s not wrong, but it’s not totally truthful either. We have established that one megahertz is one million cycles, so a 266.66MHz FSB must have 266,660,000 cycles. If we were to double that frequency to derive the AGTL+ frequency, we would get 533.32MHz or 533,320,000 cycles. As the rise of the clock and fall of the clock can both perform a transfer, that means we must multiply the AGTL+ frequency by two (533.32m*2) to get our final number of transfers per second, which is 1,066,640,000T/s. If we divide that number by one million to get MT/s instead of T/s, we come to our final figure of 1066MT/s. Doesn’t that 1066 number look oddly familiar?

In the days of SDRAM, a single clock cycle yielded a single transfer. Multiplying the speed of the RAM by the width of the bus indicated the amount of memory bandwidth available to the system. How were manufacturers going to reconcile the notion that their DDR, with two transfers per cycle, did double the workload of SDR at the same frequency? Their decision was obtuse but effective: If SDR did 133MT/s at 133MHz, and DDR did 266MT/s at 133MHz, then DDR should be advertised according to how many megahertz would be required of SDRAM to achieve the same result. The notion of doubling the actual frequency of the module to give it its “DDR Speed” was born. This antiquated idea has been carried forward to both DDR2 and DDR3.

[Castout]

Oh I see I know nothing about the new DDR3.

[Arclight]

Comes down to:
SDRAM > 1 transfer per clock
DDR > 2 transfers per clock
DDR2 > 4 transfer per clock
DDR3 > 8 transfers per clock

With each new "tech level", bandwith is doubled. Memory is about 2 things: bandwith and latency. Bandwith refers to how much data can be tranfered in a given timeframe (exampl: 1GB per second). Latency refers to how long it takes for a command to be completed. (example: data is requested by something and 80 nanoseconds later it gets it).

If a lot of small things are requested from memory, scathered over a lot of different adresses, latency is more important. If a large, continues block of data is requested, bandwith is more important. As far as I know, latency has a bigger impact on gaming performance.

CAS 4 DDR2 and CAS 8 DDR3 offer practicaly the same latency, but DDR3 offers double the bandwith (at same bus-speed). DDR3 is also more energy efficient, leading to reduced temps. DDR3 prices are now at the same level as DDR2 was at the time I bought my memory.

[Castout]

Hey thanks you make it easy to understand.

Doh now I want DDR3...but wait my mobo doesn't support it arrrghhhh

[Arclight]

I have the same problem.

If you're interrested in new memory, just get low latency DDR2 and you should be fine.