Can I change a DDR 333 board to support DDR 400 without OCing?

[bladephoenix]

Hi. The following is my system that will be the focus of this little 'experiment' :

P4 2.53 Northwood s478 w/ stock heatsink and fan
Gigabyte PE667 Pro (Intel 845PE chipset)
1GB Kingston 400 DDR RAM (Just upgraded from 512MB Kingston 333 DDR Ram)
ATI AIW Radeon 9800 8x AGP (Currently running in 4x AGP)
Enermax 420W PSU
TT Tsunami Case with stock fans

Here is what I want to do: This board (being an ol' 845PE chipset), only supports up to 333 DDR and 4x AGP. I want to take advantage of the 400 DDR RAM and, if possible, bump up the AGP to 8x to take advantage of the 8x AGP card. I have the following OC options in BIOS:

- CPU Clock Radio (Can only set if multiplier is unlocked -- Currently set to the default of 19 for this CPU)
- CPU Host Frequency (can change to anything from 100Mhz to 355 Mhz -- Currently set at the default of 133 Mhz for this CPU)
- CPU Host/DRAM Ratio (can change to 2.0 or 2.5 -- Currently set at 2.5)
- Fixed PCI/AGP frequency (can change from 33/66 to 50/100 -- Currently set at the default of 33/66)
- DIMM Overvoltage Control (can change from Normal, +0.1V, +0.2V, +0.3V -- Currently set at default of Normal)
- CPU Overvoltage Control (can change from Normal, +0.1V, +0.2V, +0.3V -- Currently set at default of Normal)
- AGP Overvoltage Control (can change from Normal, +0.1V, +0.2V, +0.3V -- Currently set at default of Normal)

This is default. 19 multiplier x 133 Mhz frequency = 2.53Ghz CPU. Host/DRAM Ratio 2.5 x 133 Mhz frequency = DDR 333.

Now, I was thinking this: I can change the CPU Host Frequency to 160Mhz. This would mean Host/DRAM Ratio 2.5 x 160 Mhz frequency = DDR 400. I wouldn't even have to adjust the voltage, since the new Kingston RAM is supposed to run at DDR 400. However, this would also mean that the CPU would have to be overclocked -- 19 Multiplier x 160 Mhz = 3.04 Ghz. This, of course, is not a bad thing, but my system idle is at minimum 42C with the default stock cooling fans listed above. At full load, it goes up to a maximum of 50C. I don't think OCing the CPU would work too well.

So...that would mean I would have to change the mutliplier of the CPU, only I don't know how to do that...or even if you can. Is is possible to do this? If it isn't...is there some way I can still accomplish my goal of increasing RAM speed without OC the CPU?

Regarding the AGP, I know that AGP speed is keyed by voltage -- 3.3V = 2x, 2.5 = 4x, etc. So does this mean if I increase the AGP Overvoltage control I can get AGP 8x? If so, what is the voltage I would set it at for AGP 8x?

Sorry for the long post. This is my first time doing this, so I wanted to describe everything I am doing, in case someone can point out I am doing something wrong. Although if I am doing something wrong and I burn something out...well...I guess I will have to find someway of getting my X2 a little early

 

[GonzoDaGr8]

bump up the AGP to 8x to take advantage of the 8x AGP card.

Don't believe that this is even possible in any way..Even if it was, You are never even gonna saturate a AGP 4x bus..

 

[theMan]

no, you cant do any of these things. you cant overclock your agp bandwidth. also, you have to increase the fsb (overclock it) to increase ram speed.

 

[GonzoDaGr8]

Only way tp get your board to fully use DDR400 is to bump the FSB up to 200.. I really don't think that your 2.53 P4 or the 845 chipset will like that very much( your P4 would be running at 3.8 ghz). You can certainly try though by bumping up the fsb until it stops POSTing and a voltage bump don't help.

 

[tyborg]

first off, I'd bump the FSB to 200 and lower the multi however much you want. Also, while we're on the topic, when you up the clocks, but not the voltages, do the temps still go up?

 

[bladephoenix]

Originally posted by: tyborg
first off, I'd bump the FSB to 200 and lower the multi however much you want.

How do you lower the multi though?

Originally posted by: tyborg
Also, while we're on the topic, when you up the clocks, but not the voltages, do the temps still go up?

I had thought that the temps only increase when you up the voltage. Of course, if you don't up the voltage, the RAM or CPU doesn't have enough power to run at the OCed speed, so it is necessary to up the voltage. However, in the case, I'm not really trying to OC, since the RAM is already DDR 400. What this is, more or less, is telling the Mobo the RAM is overclocked in order to take advantage of the speed the RAM already has non-OCed.

 

[bladephoenix]

Originally posted by: GonzoDaGr8
Only way tp get your board to fully use DDR400 is to bump the FSB up to 200.. I really don't think that your 2.53 P4 or the 845 chipset will like that very much( your P4 would be running at 3.8 ghz). You can certainly try though by bumping up the fsb until it stops POSTing and a voltage bump don't help.

I have a VERY bad feeling that bringing it up to 3.8 Ghz would work But why does the FSB have to be at 200 though? If I make the FSB 160, and scale it by 2.5 ratio, wouldn't that be the same thing?

 

[magomago]

If you want to lower the multiplier, have good connections and get a P4 Engineering Sample Otherwise its near impossible

 

[bladephoenix]

Originally posted by: magomago
If you want to lower the multiplier, have good connections and get a P4 Engineering Sample Otherwise its near impossible

Thanks

Actually I think I will just OC the CPU. Imma just going to bring the frequency up from 133 to 160. With the CPU/Memory ratio at 2.5, that should make DDR 400. I believe this will make the CPU 3.04 Ghz (19 x 160 Mhz).

How much voltage should I expect to raise it by? +0.3V? I think that the standard voltage right now on this CPU is 1.75V. How much should I expect the CPU to rise? I believe that the normal idle temp right now is around 42C, load at about 48-50C. The safe line is supposed to be around 60C.

Think this will work with only stock Intel/TT Tsunami fans?