How to Overclock

cube_

cube_

Mega Geek
First off, let me state my specs:

CPU: Pentium D 3.0GHz Presler 925 FSB 800
MOTHERBOARD: MSI P6N nForce650i FSB 1066/1333
RAM: G.SKILL 2x2GB (4GB) DDR2 800, timing 5-5-5-15 (cas latency 5)

I went into my BIOS and changed my original CPU FSB from 800 to 1066. With that said... i overclocked it from 3.0 to 4.0. My temps are around 30-40C idle time and 55-60C whe playing games so no complaints there.
My motherboard has an FSB speed of 1066/1333. So my questions:

Whats the difference between a BUS speed and FSB frequency?
Whats the CPU/DRAM ratio supposed to mean? (1:1)?
RAM - What should i set my memory FSB to for best performace to match an FSB of 1066?
RAM - Should i fool around with the CAS latency numbers?
What is D.O.T. control?

PICTURES ARE ALL HERE FOR MY CURRENT CONFIGS:

BIOS - FSB clock
BIOS - What should i change RAM clock too?
BIOS - Advanced DRAM Configuration (CAS and others)
D.O.T. Control?
PC Wizard Specs

I HOPE THIS ISNT TOO MUCH TO ASK
I would greatly appreciate it if someone would go through each step by step. This is one topic that im very fragile on! :x:
 
First off a 800 fsb jump to 1066 is one risky jump! If your cpu is an 800mhz fsb one id go back to 800 and start again!

Test your overclocks extensively. I used to use prime95 for cpus and memtest86 for ram. Do each for a long time! 24hrs will prove a good overclock.

Whats the difference between a BUS speed and FSB frequency?
Sorry for a silly sounding answer but a BUS speed id the speed of a bus. A bus being the travel of data. There is a fsb, pci bus, mem bus etc. You can get dual channel buses, mulitplied buses etc.
The front side bus is a bit like an artery through your pc. Many buses in the pc are some sort of multiple of the fsb. Thats why when you increase your fsb you also increase the mem speed and pci bus.

Whats the CPU/DRAM ratio supposed to mean? (1:1)?
The cpu is running at a particular fsb.... say 400mhz and because your ram also runs off the fsb this must also run at 400mhz (1:1 ratio) But if you have 533mhz ram it not running at its full potential so change the cpu:dram ratio to 3:4 and the cpu bus is 400mhz and the mem bus is 533mhz. [(400/3) x 4]=533.

Its good to get the mem bus running quick so that the data bandwidth matches the cpu data bandwidth... or better.

Id leave the cas latency's for the time being. They take loads of fiddling and to not much of a performance difference. The cas latency will show the most noticeable difference. Increase the number is you think the ram is unstable.... but the other settings do actually do something, it just doesnt seem like it at first! Id read wiki on that...
SDRAM latency - Wikipedia, the free encyclopedia

D.O.T control... never heard of it! But maybe its preconfigured overclocks?
 
First of all, thanks for replying :D

I downloaded Prime95 for MultiProcessors since i have a Pentium D. So when i open it... another sub window pops up... should i select custom? And if yes... what configurations should i insert?

zeus said:
Whats the CPU/DRAM ratio supposed to mean? (1:1)?
The cpu is running at a particular fsb.... say 400mhz and because your ram also runs off the fsb this must also run at 400mhz (1:1 ratio) But if you have 533mhz ram it not running at its full potential so change the cpu:dram ratio to 3:4 and the cpu bus is 400mhz and the mem bus is 533mhz. [(400/3) x 4]=533.
Click to expand...

Actually, my memory and cpu both have a matching bus speed (800). So if i wanted to overclock my cpu to 1066... this means now i would have to match my ram to the same fsb speed? or would it be ok to just leave it since the ram WILL work at its full potential?

zeus said:
D.O.T control... never heard of it! But maybe its preconfigured overclocks?
Click to expand...
Hm good thought... i think ill leave it alone though

Thanks again, and sorry for all these questions. Like i said... im very fragile on this topic. Sometimes its so confusing i just give up and try again another day :doh:
 
You dont have to match your mem speed to your fsb but if you can then you'd might as well. Now we have dual channel ram mem bandwidth is less of an issue. Your ram has a 12.8gb/s potential bandwidth whereas a 1066mhz bus has about 8.5gb/s potential so your ram covers it nicely at 800mhz.
 
Hey zeus... i don't understand what this means. Maybe you can tell me?

RESULTS.TXT
Code: 
[Mon Dec 24 12:11:22 2007]
Self-test 1024K passed!
Self-test 1024K passed!
[Mon Dec 24 12:28:22 2007]
Self-test 8K passed!
[Mon Dec 24 12:34:14 2007]
Self-test 8K passed!
[Mon Dec 24 12:50:34 2007]
Self-test 10K passed!
[Mon Dec 24 12:56:06 2007]
Self-test 10K passed!
[Mon Dec 24 13:16:08 2007]
Self-test 896K passed!
[Mon Dec 24 13:27:32 2007]
Self-test 896K passed!
[Mon Dec 24 13:41:02 2007]
Self-test 768K passed!
[Mon Dec 24 13:54:43 2007]
Self-test 768K passed!
[Mon Dec 24 14:03:50 2007]
Self-test 12K passed!
[Mon Dec 24 14:18:51 2007]
Self-test 12K passed!
[Mon Dec 24 14:28:21 2007]
Self-test 14K passed!
[Mon Dec 24 14:35:30 2007]
Self-test 14K passed!
[Mon Dec 24 14:45:41 2007]
Self-test 640K passed!
[Mon Dec 24 14:52:46 2007]
Self-test 640K passed!
[Mon Dec 24 15:01:51 2007]
Self-test 512K passed!
[Mon Dec 24 15:08:51 2007]
Self-test 512K passed!
[Mon Dec 24 15:18:16 2007]
Self-test 16K passed!
[Mon Dec 24 15:24:07 2007]
Self-test 16K passed!
[Mon Dec 24 15:34:20 2007]
Self-test 20K passed!
[Mon Dec 24 15:40:03 2007]
Self-test 20K passed!
[Mon Dec 24 15:49:54 2007]
Self-test 448K passed!
[Mon Dec 24 15:55:31 2007]
Self-test 448K passed!
[Mon Dec 24 16:05:52 2007]
Self-test 384K passed!
[Mon Dec 24 16:11:09 2007]
Self-test 384K passed!
[Mon Dec 24 16:20:54 2007]
Self-test 24K passed!
[Mon Dec 24 16:28:32 2007]
Self-test 24K passed!
[Mon Dec 24 16:36:35 2007]
Self-test 28K passed!
[Mon Dec 24 16:44:14 2007]
Self-test 28K passed!
[Mon Dec 24 16:53:53 2007]
Self-test 320K passed!
[Mon Dec 24 16:59:38 2007]
Self-test 320K passed!
[Mon Dec 24 17:11:25 2007]
Self-test 256K passed!
Self-test 256K passed!
[Mon Dec 24 17:27:45 2007]
Self-test 32K passed!
[Mon Dec 24 17:32:48 2007]
Self-test 32K passed!
[Mon Dec 24 17:45:03 2007]
Self-test 40K passed!
Self-test 40K passed!
[Mon Dec 24 18:00:39 2007]
Self-test 224K passed!
Self-test 224K passed!
[Mon Dec 24 18:17:45 2007]
Self-test 192K passed!
Self-test 192K passed!
[Mon Dec 24 18:33:39 2007]
Self-test 48K passed!
Self-test 48K passed!
[Mon Dec 24 18:49:53 2007]
Self-test 56K passed!
[Mon Dec 24 18:55:46 2007]
Self-test 56K passed!
[Mon Dec 24 19:07:37 2007]
Self-test 160K passed!
Self-test 160K passed!
[Mon Dec 24 19:24:53 2007]
Self-test 128K passed!
Self-test 128K passed!
[Mon Dec 24 19:40:20 2007]
Self-test 64K passed!
Self-test 64K passed!
[Mon Dec 24 19:57:16 2007]
Self-test 80K passed!
Self-test 80K passed!
[Mon Dec 24 20:13:30 2007]
Self-test 112K passed!
Self-test 112K passed!
[Mon Dec 24 20:29:59 2007]
Self-test 96K passed!
[Mon Dec 24 20:35:01 2007]
Self-test 96K passed!
[Mon Dec 24 20:49:19 2007]
Self-test 1280K passed!
Self-test 1280K passed!
[Mon Dec 24 21:05:56 2007]
Self-test 1536K passed!
Self-test 1536K passed!
[Mon Dec 24 21:21:55 2007]
Self-test 1792K passed!
Self-test 1792K passed!
[Mon Dec 24 21:38:07 2007]
Self-test 2048K passed!
Self-test 2048K passed!
[Mon Dec 24 21:53:17 2007]
Self-test 2560K passed!
Self-test 2560K passed!
[Mon Dec 24 22:09:38 2007]
Self-test 3072K passed!
Self-test 3072K passed!
[Mon Dec 24 22:25:32 2007]
Self-test 3584K passed!
Self-test 3584K passed!
[Mon Dec 24 22:43:05 2007]
Self-test 4096K passed!
Self-test 4096K passed!
[Mon Dec 24 22:59:14 2007]
Self-test 1024K passed!
Self-test 1024K passed!
[Mon Dec 24 23:17:00 2007]
Self-test 8K passed!
Self-test 8K passed!
[Mon Dec 24 23:32:06 2007]
Self-test 10K passed!
Self-test 10K passed!
[Mon Dec 24 23:49:20 2007]
Self-test 896K passed!
Self-test 896K passed!
[Tue Dec 25 00:05:32 2007]
Self-test 768K passed!
Self-test 768K passed!
[Tue Dec 25 00:22:23 2007]
Self-test 12K passed!
Self-test 12K passed!
[Tue Dec 25 00:38:36 2007]
Self-test 14K passed!
Self-test 14K passed!
[Tue Dec 25 00:55:37 2007]
Self-test 640K passed!
Self-test 640K passed!
[Tue Dec 25 01:10:57 2007]
Self-test 512K passed!
Self-test 512K passed!
[Tue Dec 25 01:27:39 2007]
Self-test 16K passed!
Self-test 16K passed!
[Tue Dec 25 01:45:19 2007]
Self-test 20K passed!
Self-test 20K passed!
[Tue Dec 25 02:01:52 2007]
Self-test 448K passed!
Self-test 448K passed!
[Tue Dec 25 02:18:49 2007]
Self-test 384K passed!
Self-test 384K passed!
[Tue Dec 25 02:35:10 2007]
Self-test 24K passed!
Self-test 24K passed!
[Tue Dec 25 02:51:40 2007]
Self-test 28K passed!
Self-test 28K passed!
[Tue Dec 25 03:08:27 2007]
Self-test 320K passed!
Self-test 320K passed!
[Tue Dec 25 03:24:29 2007]
Self-test 256K passed!
Self-test 256K passed!
[Tue Dec 25 03:39:40 2007]
Self-test 32K passed!
Self-test 32K passed!
[Tue Dec 25 03:57:52 2007]
Self-test 40K passed!
Self-test 40K passed!
[Tue Dec 25 04:13:26 2007]
Self-test 224K passed!
Self-test 224K passed!
[Tue Dec 25 04:29:04 2007]
Self-test 192K passed!
Self-test 192K passed!
[Tue Dec 25 04:45:28 2007]
Self-test 48K passed!
Self-test 48K passed!
[Tue Dec 25 05:02:23 2007]
Self-test 56K passed!
Self-test 56K passed!
[Tue Dec 25 05:18:32 2007]
Self-test 160K passed!
Self-test 160K passed!
[Tue Dec 25 05:34:43 2007]
Self-test 128K passed!
Self-test 128K passed!
[Tue Dec 25 05:50:45 2007]
Self-test 64K passed!
Self-test 64K passed!

PRIME.TXT
Code: 
V24OptionsConverted=1
SendAllFactorData=1
StressTester=1
UsePrimenet=0
MinTortureFFT=8
MaxTortureFFT=4096
TortureMem=875
TortureTime=15
Left=238
Top=20
Right=923
Bottom=704
W0=0 0 1010 63 0 -1 -1 -4 -23
W2=0 63 1019 358 -1 -1 -1 -1 -1
W3=0 358 1020 680 -1 -1 -1 -1 -1

[PrimeNet]
Debug=1
 
I REALLY REALLY want to warn you. The Pentium D series is an absolute crap processor and ALSO runs EXTREMELY hot at even stock speeds. You REALLY need to watch the temperature of your proc, as it is going to skyrocket overclocked.
 
Is it really? Because when i overclocked it to 4.0... temps were 30-35 idle and 50-55 while playing games. Is that much of a risk?
 
I wouldnt want to run my P4d above 55c. I dont know from experience or google what are reasonable temps for your cpu but 55c is probably verging on high.

Your first attachment obviously has 6hrs of passes... which is good! Was that for your RAM?
Im not sure what to make of your prime.txt attachment. Seems like they are settings to me but the debug=1 might be something. Was that prime95? Did it end itself within hours?
 
actually i stopped the program myself after about 13 hours or so because i didn't know what was going on lol and yeah it is Prime95. I don't understand what they mean by "128k passed" or anything like that.

I restored my default fsb settings since im not sure if what i previously set it to was high or not
 
As long as you don't see it stopping or get errors, that's fine.

It runs different tests and lets you know when it's done. They're different lengths of data thrown at the CPU to see if it cracks under pressure, so to speak (not physically crack).
 
That would be awful if a program could litteraly crack my $199 CPU :doh:

So how can i tell from these thrown numbers, what GHz it can reach up to? (basically... what, from these numbers, can i set my fsb to?)

I have set it to its default 800 after posting this thread since i wanted to make sure that what i was doing was safe.
 
Those numbers wont give you an indication of how far you can overclock your cpu. What they do tell you is that the cpu and ram has been run flat out for ages and ages and neither have made any considerable mistakes.

All your pc is, at the end of the day, is a mighty number crunching calculator. The quicker it does it sums the more likely it is to get some of the sums wrong. If it gets a fair few wrong then the software will get into a pickle and crash. Or even windows. Your pc could be getting sums wrong all the time and you wouldnt even notice! If you get to the point where windows is crashing or even BIOS upon boot then you must be getting an extortionate number of sums wrong and the pc is really hanging on by a thread.
This is why its important to test your overclocks extensively.

Running a game for an hour will help determine your operating temps (because your cpu will be running at 100% capability) but it doesnt give you an indication to how the cpu is coping.

Prime95 is basically a program which is searches for a prime number which people know is possible but have yet to find. It involves testing gazillions of numbers for particular requirements... which a cpu loves to do! So its a good cpu test program. (I take it you ran the crunch test?) Its when prime95 does the tests it can determine whether the cpu has made a mistake or not (probably because of the simple requirements of a prime number)

Think of RAM as a waiting room for the sums to sit before the cpu tackles them. When the cpu is ready it will send a request for the next set of sums. Its does this quickly (8.5gb/s on a 1066mhz fsb) and then the ram has to send sums to the cpu quickly. Ideally just as quick if not quicker than the cpu requests them. (12.8gb/s on a dual channel 800mhz mem bus)
When you overclock your ram you are getting the sums to run from the waiting room to the cpu faster than they are capable of. If you tell them to run too fast they will fall over and wont reach the cpu. So the cpu, which runs to a strict schedule will skip the late arrivals and move onto the next set of sums. Like before, the odd one or two mistakes by your pc isnt the end of the world but as soon as you miss a series of instructions or quite a few random ones the software or BIOS gets confused and crashes.

The memtest86 is just a way of sending different instructions down the mem address bus. Note that if memtest86 fails its not always down to the ram! There is like a mini RAM on your cpu (L1, L2 and L3 caches) These might also be failing. Its not good practice to call the caches ram! (I dont think they are randomly accessible but im not sure) But they do something similar to ram. memtest86 will expose issues with the caches too. If you do hit problems when using memtest86 its best to look at the ram first.
 
Thanks for all the info everyone and especially zeus... ill be posting some news after my week snowboarding trip to vermont! :P
 
You must log in or register to reply here.
Back
Top