Confused about Overclocking?

[mogur]

Hi. Nice to meet you all. I want to thank Nathan, CoolJoe, Roger, and all other contributors here for sharing their wealth of information. It is a real pleasure to see so many people with the willingness and patience to guide the inexperienced. A few seem too lazy to even read the thread that they are posting to, and ingrateful if not spoonfed the info they demand. But I think the majority are more than grateful for the opportunity to be part of a learning community. In that regard, I was hoping the following might help some newcomers piece together a part or two of the puzzle.

Overclocking is the art of squeezing the most performance out of your computer SYSTEM. In an ideal computer, you would only have to optimize the performance of each COMPONENT, one at a time, and you're done. But current computers are not ideal, and that's where confusion sets in. Consumer P4 micros are multiplier locked, and this is the root of most of the confusion. If they were not locked, you could tweak your processor performance in rough steps by bumping up the multiplier, independent of any other components. But Intel has left us with only one toy, and that is system speed. By juiceing up the FSB we can still reach maximum processor speeds. But since the FSB also speeds up memory, we quickly hit a brick wall when the memory maxes out. Memory simply doen't have the overhead that your processor does. So, to continue tweaking your processor's speed, you are forced into limiting the frequency to your memory. The only tool in current systems to accomplish that feat is the FSB frequency divider. And since it only gives you a choice of 1/1, 5/4, and 3/2, you are obviously only given a very coarse adjustment.

So, let's say you got to 230Mhz FSB and became unstable. Your memory is getting goofy at this point, so you have to switch to the 5/4 divider. This knocks the frequency to your memory down to 184Mhz. This is a performance hit, because your memory is running 20% slower. But hold on, once you juice the FSB again, then not only does the memory start speeding up again, but the processor is also continuing its upward path. Think of it as shifting gears, at first you lose a little power, but when the rpms catch up, you will be going much faster. When you hit 288Mhz FSB, your memory is running at 230Mhz again and your 2.4C processor is at 3.45Ghz. Shifting to the 3/2 divider at this point knocks the memory back down to 192Mhz, allowing you to continue your journey. Somewhere along the way, your processor will max out and the luck of the draw will then be your bragging rights.

Now this little senario is not quite that simple in reality, of course, but it's the outline of what we are trying to accomplish. Along the way, your components may not cooperate as I have so loosely portrayed. You may have to free up the timing of your memory (i.e. 3,8,4,4), or up your memory and core voltages to allow them to reach higher frequencies, and of course, you must lock down the agp/pci bus so they don't get swept up in the FSB race. These secondary tweaks must be implemented with caution. Some, like the loosening of the memory latency, is just a small sacrifice for a larger gain. But upping the core voltage can actually damage your pocketbook. Take Nathan's advice and only modify the core voltage after all else fails, and then only in moderation. Aggressive core voltages don't gain much anyway.

If you're wondering what memory to buy, the above story illustrates the importance of memory headroom. The minimum should be rated for 200Mhz operation. Here is where a lot of confusion comes to the inexperienced. Memory that is rated for 200Mhz actual use (for our purposes) is called DDR400. Another way to refer to it is PC3200. And of course, Intel refers to a dual channel, double data rate 200Mhz bus as a 800Mhz FSB. This terminology quagmire is stupifying at first, but quickly becomes easy to understand when you realize that marketing people will always multiply out any 'dual' or 'quad' design specification by what a frequency meter will actually display. Anyway, back to memory headroom. The nominal ratings of most memory will allow some 'stretching' to higher frequencies. But if you are planning on OCing, start with the fastest memory that you can afford. Back down from 1 gig to 512 megs if you have to, but get some DDR500 or DDR550 (PC4000 or PC4400). At these speeds you don't even have to worry about brand, because right now only the top manufacturers are making these chips. Corsair even tests their DDR550 memory in a 275Mhz Canterwood setup (Asus P4C800-E). Don't mess with low latency chips, either. I know that the lower the latency, the better the performance, but in this case, there is a gotcha. Low latency modules have firmware built in that won't allow higher latencies. This will cripple it when the latencies MUST be relaxed to reach the maximum overclocking potential of your processor.

[Google]

[JayDubya]

very well explained mogur. i too would also like to thank EVERYONE that has contributed to this website, especially Nathan, Roger, CoolJoe, and Icyrus76 along with the countless others. thank you all very much for spending the time and putting forth the effort [and patience is not to be excluded] to help us all out.
_________________
JayDubya aka JW Jay JD ^> ﺵ

[diro]

Awesome 1st post, you need to stick around here.
_________________
DiRoLoKo!! I fix robots and wear a bunny suit for a living.....the best job i ever had, most money i ever had :)

[[TN] Nathan]

Mogur,

Very well done. Thank you for your contribution and I am considering making this a sticky for everyone to read.
_________________
Owner & Administrator
www.Tweaknews.net
www.Pocketbookpinch.com

[-verTo-]

Just reading what mogur wrote gives you a more firm grip on what you are trying to acheive.
_________________
Aspire X-Alien 420W
ABIT IC7 875P
SP-94 w/ 64CFM
Pentium 4 2.6 @ 3.3 255FSB
Vcore:1.60 Vdimm:2.7
OCZ PC4200 Performance Series(2x256) 1:1
Maxtor 80gb SATA
Radeon 9800 Pro

Stock Video Card w/ OC proc:
3dmark03 - 5950
3dmark01 - 19593

[mogur]

Thank you, all. Memory for overclocking is not a trivial subject, and as I try to learn a little more about ddr, I now think that less than 1 gig of memory is a serious handicap to either gamers or content creators. Sure would like to see more reviews of the cheap modules, there just might be some pearls there. Because I'm cheap. But not easy.

[[TN] Nathan]

It's a sticky now.
_________________
Owner & Administrator
www.Tweaknews.net
www.Pocketbookpinch.com

[Trimcz]

I have:
ASUS P4C800
2 x 512MB 3200 Adata RAM
P4 2.4 GHz HT

I was trying to follow Nathan's step by step instructions about overclocking my PC, but I simply cannot move from where I begun.

You said, that I can start raising FSB by increments of 5 MHz, but how do I do it? My BIOS gives me these starting options: CPU external freq. at [200] (which as I believe means 200x12=2.4GHz CPU speed) and than DRAM freq. at 400. BIOS let me select only from 4 options here - AUTO, 266MHz, 333 MHz and 400 MHz.
So how could I change DRAM Ratio CPU:DRAM to 3:2 or 5:2 ?

Even If I would lower DRAM freq to 266MHz, I would have to set CPU external freq to 399 !!! That would burn the CPU for sure, because that gives 4.788 GHz speed, right?

There is no "divider" option in BIOS and all I did was locking up AGP/PCI freq. at 66/33. Would it be possible to change it to 72.73/36.36 ? How much influence this change has on overclocking?

Now regarding mem timing I changed it from 2.5-4-4-8 to 3-4-4-8 in bios, but I didn't get any performance gain. I guess I would have to be able to work out with DRAM/CPU freq. as well, right?
Weird think is, that if I ran CPU-Z and check timing, it shows 2.5-3-3-6 timing, but in BIOS I have 3-4-4-8. What's the problem?

I tried to raise mem voltage and CPU voltage by your instruction together with increasing of CPU external freq, just by 5 MHz and PC didn't boot.

Another Qs are only about some BIOS options, that I don't know what they are good for and if I should change them as well:

DRAM Idle Timer ?
DRAM Refresh Mode ?
MPS Revision?

I am sure, that I am doing something wrong and I woud really appreciate your help.

Thanks for any help in advance.

[ToggleHead]

Ok first off......i would recommend learning a lot more info about what you are about to do before you just go ahaed and doit.......but.......allow me answer a few of your questions as i have a similar board.

AGP/PCI ALWAYS at 66/33
cpu external freq IS your FSB
the ram divider are as follows......400mhz = 1:1 333 = 5:4 266 = 3:2

you dont HAVE to set your FSB in proportion with your RAM divider, alas this is where the art of OCing comes from, finding the correct ratio between FSB and ram speed and timings. You rmultiplier is locked since you have a P4 just like mine. so us pentium guys have one less thing to worry about....=]

You got a great chip.......ask some questions and you'll get it
_________________

[Trimcz]

Thanks ToggleHead,

Yeah, I am trying to learn, believe me. And I am not going to do some crazy stuff just to get more and more.
I understand better now, I just got a little confused by explanation of how to set External CPU frq x DRAM frq.

Anyway thanks for reminder and help.

Trim

[[TN] Nathan]

Set your memory voltage to 2.8

Set your cpu voltage to 1.6

Set your DRAM freq. to 333 which is the 5/4 divider

Ram timings at 3-8-4-4

AGP/PCI locked at 66/33 ONLY

Maybe bump the AGP voltage to 1.6

Turn the Ai overclocking off if your board has it.

Now up your FSB up in 5 Mhz increments and see how high you can go.
_________________
Owner & Administrator
www.Tweaknews.net
www.Pocketbookpinch.com

[Trimcz]

Thanks Nathan too..

You guys rock big time and thanks for sharing it with us.

Trim

[ToggleHead]

thats why we're here......=]
_________________

[Xal]

I Just stumbled across your forum today, read a few posts and the decided it was really cool so I joined. You guys seem to know your stuff! I've been a techy for about 6 years now and if there's one thing I've learned its that no matter how much I learn I'll never learn it all! In fact it seems that the more I do learn the more there is too learn. Great site guys, keep spreading the knowledge. You never know some newbe might actually teach you something, lol.
_________________
Phenom II x4 955 @ Stock
Asus M3N78-EM
4gb Corsair XMS2 DDR2 667 @ 800
1gb Powercolor Radeon HD 5850 @ Stock
X-fi Extreme Audio PCI E
Nexus 600W Silent PSU
Nexus Fans
Custom case

[ToggleHead]

WELCOME

Youre damn right.....stick around........im sure we can swap some knowledge....=]
_________________

[Noxide]

yal guys are HARD CORE!!!!! This is the best comp forum i have ever been in. The O/C help post helped out alot. ( considering I'm new to sooping up computers) Thanks to everyone so very much on the help!!!!!


Xavier M
A.K.A Noxide

[ToggleHead]

glad to help.....=]
_________________

[Josh]

[Hoedizzy]

I have a feeling that this forum is going to really skyrocket soon.....i've been spreading the word ever since i've joined. This place is great!

[Xal]

*Velcome, velcome* . This is the best forum on the web, I'm sure you'll enjoy it here

Share and learn
_________________
Phenom II x4 955 @ Stock
Asus M3N78-EM
4gb Corsair XMS2 DDR2 667 @ 800
1gb Powercolor Radeon HD 5850 @ Stock
X-fi Extreme Audio PCI E
Nexus 600W Silent PSU
Nexus Fans
Custom case