Will my P4 Presler run at 4.25ghz !!

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Recently got hold of a system (not allowed to mention name most likely) with a 3.4 presler (800mhz fsb) and 2gigs DDR2 533mhz ram. The mobo has no overclocking options whatsoever, but I noticed when I ran CPU-Z that the memory is reported as PC4300 (266mhz) as expected, but under the timings section there is an FSB/DRAM entry of 3:4. So basically the FSB is running at 3/4 of the DRAM speed or 200mhz. All as expected.

But hang on, because of the 3:4 divider, does this mean if I install some PC 5300 (333mhz) memory (which Intel says the 945 chipset supports) that the divider will adjust my fsb to 250mhz, giving me a cpu bus of 1000mhz instead of 800mhz, and an effective overall cpu speed of 250x17 or 4.25ghz !!!
 
Cheers. Thanks for the update there.

The system I got for *free*. Do you think it is worth buying some PC5400 memory, effectively increasing memory speed from 533mhz to 667mhz which I guess might offset the crap timings a bit (4,4,4,12) ? I think 667mhz is about as much as the board will support.
 
What I don't understand is that on AMD systems your memory usually defaults to DDR400 speeds, and you overclock the memory with dividers and/or upping your bus or htt. But on Intel boards, does the memory always run at the rated speed independent of your cpu. I guess what I am asking is if I get memory that is rated at 667mhz will it run at this, and then the mobo will use a divider to keep the cpu at stock.
 
That's correct

The Intel chips don't have a memory controller on board - they have to talk over the FSB to access the memory. The FSB of the chips and the memory speed are bottlenecks. If you increase the memory speed you help to reduce this bottleneck, even if the CPU runs out of sync

As the AMD chips have a memory controller on board and no FSB they remove these bottlenecks. If you run the memory higher than the HTT speed you won't get any real benefit at all - even running the memory slower doesn't really hurt the performance of the CPU, not like the Intel CPUs anyway
 
Try and run some benchmarks as I have found that DDR2-533 Ram @ 3:4 gives an extra 2000+ marks in Sandra and the system feels a lot quicker overall as for me it is running an FSB of 266 compared to the stock 200.

Because Intel CPUs quad pump the data it is effectively 1066 FSB vs 800.

If your mobo supports upping the FSB speed by typing it in manually then that is the best way to overclock as with the ram you already have even if it is cheap stuff should still hit 1100-1150 FSB which x CPU multiplier gives you a good overclock.

Most non-corporate based mobos allow you to lower the CPU multiplier to x14 which then allows them to run cooler as they are getting less internal stress but the increased FSB speed strains the mobo more but as they should be designed to handle it not an issue and free performance for you (just ensure you keep temps+vcore under control).

No need for you to get other Ram just try and find if you can gain access to hidden bios settings with another key combo or bios version. Must be possible otherwise how did they program the fixed fsb speed in the 1st place.

However even after all of this you will not be able to get much more than 4Ghz and in real world performance that will not translate to much more than 10% if that plus your temps will increase greatly as the Presler is 2 x P4s bolted together!
 
Unfortunately my system has ZERO overclocking options. You can probably guess what company makes it, but I 'aint complaining as I got it for an indefinite period to do some Vista beta2 testing.
 
get a decent mobo for a start :)

Increasing DDR2 speeds (by running a higher divider) will give you better memory bandwidth, especially write bandwidth ;)
Even using these mems they should go up to 700-800mhz ddr2 speeds (depends how good these sticks are...) with approx CL4 4-4-12 timings which are "ok" for ddr2 speeds on cheap ddr2 sticks.
 
monkeypants said:
It's some OCZ PC-4200 EB. I don't think they make it anymore, but it's ace stuff.
Click to expand...

its old and rubbish ;)

anyway @ the op, if you buy some better memory you'll still have to change the divider otherwise you'll just end up with expensive memory doing the same speed as the old lot.
 
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I borrowed some 667mhz ddr2 and installed it in my Dimension 9150, and it runs at 667mhz - so problem is now solved. As for the post about the motherboard being rubbish - well if you got a full system for zero cost, I don't think you would be complaining, especially with a 3.4 pressler dual core which feels quiet nippy. Just waiting on a 1900xt-x now.
 
ajgoodfellow said:
That's correct

The Intel chips don't have a memory controller on board - they have to talk over the FSB to access the memory. The FSB of the chips and the memory speed are bottlenecks. If you increase the memory speed you help to reduce this bottleneck, even if the CPU runs out of sync
Click to expand...

Wonder if you can help me also, so basicly your saying that it does'nt matter the memory is out of sync with the fsb, whats more important is having the ram run faster, why I'm saying this is b-cos i,ve been running my ddr2 533(266) @ 400(200) to match my cpu's fsb, so what do you thinks best,

1. Run my ddr2@533(266) with timeings of 4-4-4-12

or

2. Run my dd2@400(200) with timeings of 3-3-3-10

Cheers

My sys specs Intel P4 3.4, Intel D925XCV, 2Gig ddr2 533.
 
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lowrider007 said:
Wonder if you can help me also, so basicly your saying that it does'nt matter the memory is out of sync with the fsb, whats more important is having the ram run faster, why I'm saying this is b-cos i,ve been running my ddr2 533(266) @ 400(200) to match my cpu's fsb, so what do you thinks best,

1. Run my ddr2@533(266) with timeings of 4-4-4-12

or

2. Run my dd2@400(200) with timeings of 3-3-3-10

Cheers

My sys specs Intel P4 3.4, Intel D925XCV, 2Gig ddr2 533.
Click to expand...
Use memtest86 and check the memory bandwidth, my bet is that it will be higher at 533 and CL4 4-4-12 but give it a go and see which will give you best results :)
 
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