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OK.... What happened to my RAM's bandwidth when OC'd?


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I just noticed that when I boot my system, the BIOS comes up saying my RAM is Dual Channel 4300. My memory is rated as 6400, and boots as such at stock settings.

 

My OC is 400 FSB X 8 multi. I did this to run my RAM at 1:1. It's set at 800 (the lowest allowable setting at this OC on my P5B Dlx.). However, if I bump it up to 1000, it ups the bandwidth to 5300, so it does increase that way. The RAM settings go up to 1600, I believe. It seems like the board will only let it run @ 6400 if I bump the RAM speed up to 1200. There's no way my sticks are going to do that. Is this normal?

 

Thanks!

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I have exactly the same problem / question!

 

I also have an asus p5b-e..... on stock it says 6400... oc it says 4300...

 

I think its because the bios gets confused with the OC and is not sure what to rate the memory at.

 

Can anyone confirm? In cpu-z it still shows the right info, though my memory bandwidth is at <5gb/sec

 

Scanning SMBus at $0400...

Decoding DIMM #0

Memory type is DDR2

Module Rows : 97

Levels : 1.8V

Parity : NO PARITY

Refresh Rate : 7.8us

Total Size : 49664MB

Decoding DIMM #2

Memory type is DDR2

Module Rows : 97

Levels : 1.8V

Parity : NO PARITY

Refresh Rate : 7.8us

Total Size : 49664MB

 

Yapa

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OK, it's kind of a confusing issue to put into words. I'll try again:

 

My RAM is rated as DDR2800 (6400). The BIOS boot screen currently shows my RAM as Dual Channel Interleaved 4300, instead of Dual Channel Interleaved 6400 with my overclock. For my overclock, I have my CPU Front Side Bus set at 400mhz, and the CPU set at an 8X multiplier. Running DD2 RAM, I set my RAM frequency to 800Mhz to match my overclocked CPU FSB at a 1:1 ratio (allegedly to achieve optimal performance). Running my RAM at 800Mhz on this overclock, apparently lowers my bandwith to 4300, instead of the 6400 its rated at, with this motherboard. I'm able to up my RAM speed to gain the bandwidth back, but there's no way I could run stable at a 1200Mhz RAM speed (apparently what it would take to get "6400 Dual Channel Interleaved" back on the BIOS boot screen).

 

Yapa: I know exactly what you're saying. I'm here for you brother! :biggrin: As near as I can tell though, I think that this is normal. I'm screaming through SuperPi 1M@ 15.844 seconds.

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Simple. Turn up your CPU overclock. I built a PC for a person in sweden with 2 x 1GB of Corsairs DDR2-800 sticks, CAS 4. I used an Intel 975x board though. I _think_ it was by Asus. But yeah, 3.6GHz C2D 6600 (Stable up to 3.8) with a Zalman 9700 and ram running up to DDR2-900 at 4-4-4-12 produced.. Eh, I didn't save a screenshot, silly me, but it was under 15 seconds for 1 million digits.
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