memory underclocking?

[trOver]

i bought an asus p5w-dh deluxe with with a 6600. The memory i bought to go with it is rated at higher speeds than it is supposed to run at, which is 800mhz. My memory is rated at 1ghz, and right now its running at 533mhz. what gives?

btw it is a 2x1gb set of crucial ballistix, pc2-8000

 

[Roguestar]

Until you change something your memory will run 1:1 with your FSB so if your FSB is currently 266Mhz then your memory (x2 for DDR) is effectively running at 533. To run it at 800 you need to run your FSB at 400Mhz, which is a rather large overclock. Y'see, there's no point in buying performance memory for a system with a lowish FSB and high multiplier if you're not overclocking. I guess you could try tightening the timings to recoup any losses if you're not going to overclock (which would be a waste in my opinon).

 

[trOver]

Originally posted by: Roguestar
Until you change something your memory will run 1:1 with your FSB so if your FSB is currently 266Mhz then your memory (x2 for DDR) is effectively running at 533. To run it at 800 you need to run your FSB at 400Mhz, which is a rather large overclock. Y'see, there's no point in buying performance memory for a system with a lowish FSB and high multiplier if you're not overclocking. I guess you could try tightening the timings to recoup any losses if you're not going to overclock (which would be a waste in my opinon).

but why then does the motherboard advertise 800mhz memory so much? i know when i used to buy the old pc-3200 memory it always ran at that speed. your saying that the memory will always run at 2x the fsb? so on my old systems the fsp was running at 200mhz?

 

[trOver]

bump

 

[Ilikepiedoyou]

What I beleive is and I am quite the noob, is that since it is dual channel, it runs at double your FSB speed. Also that rating on the memory of 800 mhz is what it can run at properly, NOT that it will run at this. I believe if you were using DDR it run at the same speed as your FSB. If I wrong somebody correct me, because I am learning!

 

[Roguestar]

Dual Channel double the memory bandwidth so it sends 128 bits of data at a time instead of 64. The 2memory:1FSB being considered as 1:1 is because of the fact that DDR2 runs at twice the speed of the FSB in general. http://en.wikipedia.org/wiki/DDR2

 

[Lemon law]

For what its worth---with a amd processor and checking speeds with cpu-z--I noted my front side bus was showing way under preforming---but as soon as I put the cpu under some load,
I could see the bus speed throttle up to what its rated at in cpuz---so beware of some benchmarks that don't put the system under load because it will idle down somewhat automatically. Or at least my computer did.

Makes some sense when you think about it---why waste speed and build up heat when you don't need to.