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If i use 2*2GB 800MHZ DDR2 RAM, with 1333 supported bus of CPU and FSB, then CPU's performance will be downgraded? (and why?)
I know this is pretty old system, anyway i need to use it.
Fredi
Posted 2017-12-14T04:15:41.077
Reputation: 73
RAM slower than CPU supported speed?
Answers
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As pointed out in the comments, the CPU performance will not be affected per se, it will simply access memory slower (but still as fast as the memory and any associated interconnect will allow).
Regarding performance, as also noted in the comments, the system will run slower overall but to what degree (negligible or otherwise) is a guess. Likewise, whether you'll "notice" this speed reduction is not something that can be easily answered, except by trying.
Anaksunaman
Posted 2017-12-14T04:15:41.077
Reputation: 9 278
Thanks, my initial idea was "using a 1333 supported bus CPU on 800MHz RAM, mean you are wasting CPU interaction capacity a lot, so its not worth buying such high CPU, even its clock is 3.3 GHz" . so it seems i was wrong? – Fredi – 2017-12-14T22:19:41.377
Assuming I understand correctly, if you are certain you can get (or already have) a compatible 3.3Ghz CPU for your motherboard, faster is usually better. Though it likely won't improve memory access drastically, it is should be better than a slower CPU, especially for CPU bound tasks that aren't heavily memory reliant. Ultimately it's probably more up to your wallet to decide. – Anaksunaman – 2017-12-14T23:41:12.903
CPU's performance will be downgraded...please be more specific. In what way do you suspect/wonder how the CPUs performance will be affected? – I say Reinstate Monica – 2017-12-14T04:25:40.437
@TwistyImpersonator CPU and mobo are supporting up to 1333 and RAM is 800mhz.. i think this make CPU run in lower bus speed than it can? maybe I'm wrong, asking to know. – Fredi – 2017-12-14T04:38:09.360
No, it means the CPU will access the RAM at a slower speed than it (the CPU) is capable of. The CPU's "speed" (frequency) will remain unchanged. – I say Reinstate Monica – 2017-12-14T04:41:44.027
Relevant: https://en.wikipedia.org/wiki/Front-side_bus. Also note that the FSB is long gone. It's been replaced by AMD's HyperTransport and Intel's QuickPath and soon to be UltraPath Interconnect.
– I say Reinstate Monica – 2017-12-14T04:44:27.990@TwistyImpersonator OK, still this can make notable difference in overall performance? using a 800mhz supported CPU with lower clock (and lower price!) , is better choice? – Fredi – 2017-12-14T04:51:12.723
@TwistyImpersonator yes.. i heard that FSB is history.. – Fredi – 2017-12-14T04:53:17.250
Well now you seem to be asking if the overall system's performance will be impacted by using memory slower than the CPU can support. The obvious answer is of course! Will you notice it? That's a subjective question I cannot answer (and is not a good question to ask on Super User--questions here are expected to solicit definitive answers, not opinions). – I say Reinstate Monica – 2017-12-14T04:57:10.150