Right, here we go:
AMD64 Clocking
HTT is also known as FSB on Intels.
CPU multi : 12x on your CPU (4000+SD) (can be dropped down, but don't use half multi's they do weird things to memory speeds), this, multiplied by FSB = core speed. It varies depending on CPU. FX's have multi's unlocked both ways. The rest have a locked upwards multi but unlocked downwards. i.e. a 3000+ @ 1.8ghz will have a multi of 9. 9 x 200mhz HTT = 1.8ghz. The minimum is 4x, all the way up to the max of your chip.
HT (aka LDT on DFI's) multi: 1-5x this, multiplied by the FSB = the bus speed of the board i.e. 1000mhz maximum. Try to keep it under 1000mhz as often boards will crash/not boot even 1mhz over this figure. x5: 200mhz, x4: 250mhz, x3: 333mhz. These are the limits you can go up to on FSB when using a specific multi. DFI's are different though, often they can run higher than 1000mhz but it may cause some minor stability issue. I have however run 1250 (5x250mhz) but this is all the luck of the draw. It makes very little difference to benchmarks etc so most O/C'ers leave it at 3x and don't worry about it. (unless they are only using up to 250mhz FSB in which case they set 4x - you might as well).
Now onto RAM. When you overclock the FSB, you are also overclocking the RAM. Never leave the main 5 RAM settings on auto: CAS, TRCD, TRP, TRAS and Max mem clock <- this should be set to 200mhz unless you want to run on a divider. People run on dividers when their RAM can't go high enough with the FSB. e.g. the ram has a limit of 250mhz and they have their FSB set to 275mhz. The divider then splits the RAM and the FSB into a ratio. 1:1 is the best ratio i.e. FSB=RAM. A 166mhz divider changes the Ratio to 6 (FSB) :5 (RAM) i.e. a 300mhz FSB will run the RAM at 250mhz - 300:250.
Now onto the actual timings:
CAS: this has the biggest effect on memory. Try to keep it at 2 or 2.5 (depending on your RAM -I see you have TCCD like me so I'll give you more specifics). TCCD will run at CAS 2 up to about 220mhz max usually at low voltages. After this, you must use 2.5. Do not use 3 until past 300mhz at least as there is massive difference between 2.5 and 3. 2.5 offers the best stability and really is what you should leave it at.You change this setting last if you can't get stable at a particular frequency.
TRCD: This should ideally be set at 3 for high FSB. If you can't get stable at 3, use 4 but go no higher. This is the second timing you change to try to get stable. This is the 3rd setting you change to get stable
TRP: this should ideally be kept at 3 like TRCD. These two timings are very similar and ought not to exceed 4. 3 gives good performance and with the right other settings can allow good FSB.
TRAS. This is the first setting to change. It can be set from 5 to about 11 which ought to be the limit on TCCD. Once the RAM is not stable at 11, change other settings.
Order of change to get stability: TRAS (to 11 max), TRCD (to 4 max), TRP (to 4 max), CAS (leave at 2.5, don't use 3 unless you reaaaally have to).
1T/2T is known as CPC enabled and disabled on DFI's, or memory command rate on other boards. 1T is CPC enabled and 2T CPC disabled. It is the memory command rate and should always be left at 1T because although 2T allows for higher speeds, it takes a massive performance hit on the RAM and is just not worth it. Always try to keep 1T settings.
TCCD is very fussy with volts, no-one can say how well yours will do. Mine was very responsive at 2.6V up to 260mhz after which 2.9V was required. Everything in between would give me lots of memtest errors. As a general guide, your RAM shuld be able to do these settings at these speeds:
200mhz 2-2-2-5 1T default
250mhz: 2.5-3-3-5 (or 6) 1T
275mhz: 2.5-3-3-7 1T <- with the right settings. (see I have 2.5-3-3-6 1T, but that required lots of settings changes into other areas, don't ask, I just copied them from someone at Xtremesytems). If not 2.5-3-3-7, 2.5-3-3-10 or the like.
300mhz: 2.5-4-4-8 <- this is not really a guaranteed, it's all down to your specific chips. Mine did 300mhz at this speed but I haven't really tested it much, it was mildly stable.
All other settings are out of my knowledge. In this area, there is a thread at Xtremesystems which I just copied and tweaked to get my speed:
Click me. Don't use the same voltages, just find your best. This was for G.Skill RAM but all TCCD is the same.
Special Note: When overclocking, you must lock any AGP/PCI or PCI-e locks. In the case of the DFI you have, you must set PCI-e frequency to 101mhz to avoid getting screen corruptions when you set a high FSB.
An example overclock on your system to 2.8ghz from 2.4ghz stock:
HT multi x3.
HTT (FSB): 280mhz
CPU multi: x10
CPU voltage: anything up to 1.55V on air, 1.6V on water, and 1.7V on phase change. See how far you get on stock volts first then work up to reach stability.
LDT voltage, just try 1.3v
Chipset voltage, try 1.6V
RAM voltage: up to you but 2.9V max on TCCD without a fan blowing over your RAM sticks. 3.1V absolute maximum - <- don't use this though, 3.0V is all you really need max.
RAM timings, follow the 275mhz thread at xtremesystems above and adjust for 280mhz by dropping the TRAS to 8 say.
Once you have done the timings, straight in for a memtest (built into the DFI BIOS). memtest tests 5 and 8 for about 30mins each for a rough idea of stability and then the whole test for about 6 hours (overnight) to make sure. To run a specific test, type this upon entering memtest.
'c'
'1'
'3'
'5' for test 5, '8' for test 8
'Enter'
'0' <- zero.
Once memtest is done and passed, go into windows and use OCCT from
here and this runs a 1/2 hour test and will give you an idea of stability (run the stability test). Then once this has passed, run prime95 for about 10 hours I'd say, longer if you want. Then use away at your new speed.
I hope this helps. If you've got this far you're probably wondering why I just typed all this out - well Liverpool just won the Champions League last night and I'm absolutely hyper at the moment and feeling quite generous. Still in shock.
Can't get over it.
Smids. (going for a lie down now).
EDIT:
1) Made some grammatical corrections
2) Added AGP/PCI lock and PCI-e frequency warning
3) Added link to OCCT v0.91
4) Added 1T/2T memory command rate
5) Added title AMD64 clocking
6) Altered CPU multi information
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but i can't begin this guide because i can't do the following: