Discussion in 'OC Archive' started by NF7-S, Oct 29, 2003.
Sounds right. Some performance gain yes, but not overly so.
Link isn't working
The thread it was in has been deleted. Not to worry though, I saved the text in a notepad and will post again.
Right, here we go:
HTT is also known as FSB on Intels.
CPU multi : e.g 12x on a 4000+ San Diego (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. I'm using TCCD as an example as it is the easiest to work with. 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). TCCD (1GB, 2x512MB kits only) 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).
As I said, all of the above is TCCD related only, this will vary on new 2GB kits where running CAS3 isn't so much a problem. You have to check your own RAM specs to know its limits.
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 a 4000+ San Diego 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.
'5' for test 5, '8' for test 8
'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).
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
7) Generalised the guide
thx for the info smids, gonna gave that a try today, 1st time OCing, should be fun
ok quick question , on Asus Sli premium there is no Tref, is this the Max memclock, as mine is set to 400mhz at mo for ddr400, so do i need to set this to 200?
No, tref is something altogether different. Your max mem clock is your memory divider.
ok followed ya guide, mem overclocks good, but system doesent like overclocking the cpu. tried all diff speeds and voltages, might be the 10x multipler, will try 11x later. wierd tho will overclock if i let the board do it for me! , must be somthin im doin wrong.....
Could be a voltage thing. When you do auto overclocks, boards often ramp up the CPU voltage massively - quite dangerously in my opinion. This will cause stability but is damaging to the CPU. Either that, or the multi s causing it. Some CPU's are very fussy about the multi used as you say. What CPU is it?
ok thanks for the info, to think i been building comps for years, just never overclocked, only wanna get my 4000SD to 2.6!
Ahh SD4000. Should easily get there, only a 200mhz clock. 10x260 should be stable .
Max mem: 400mhz
LDT/HTT multi: 4x (might be unstable as it goes over 1000mhz HTT) or 3x (stable).
Vcore: 1.45V should do it really (might even get there on stock volts knowing these SD's.
Vdimm: dependant on RAM
RAM timings: dependant on RAM.
No CI/AGP lock as you have a PCI-E mobo. Umm those are basically the only things you need to change IIRC.
ok will test those, ram is Corsair 2GB DDR XMS3200C2PT TwinX (2x1GB) CAS2 , i got it @ 2600 at mo, but it keeps dropping my ram max mem to 266 :S wierd
ok after playing its definately ram playing me up, everytime i set to 400mhz with my timings it just crashes after checking IDE's, recomend any settings, dont wanna be on 266 :S
3700 not performing
my current setting are not good.
on CPU-Z it says:
Core speed = 1020.1Mhz
multiplier = x5.0 (when in BIOS i set it to x11) :S
HTT = 204.0 Mhz
Frequnecy = 204Mhz
FSB/RAM = CPU/5
Timing are = 2-2-2-5
Trc = 7 clocks
DRAM idle timer = 256 clocks
im kinder new to O/Cin but im strugglin now lol n ive seen so many blue screens i mite cry if i see another lol
anyone got an idea??
sounds like something is broken tbh, either your mobo or your cpu, coz it shouldnt be doing that
well i got my problem sorted, lets me keep my ddr on 400 as long as i keep the cpu multi on 12x, sat now @ 2640mhz ram @ 2.5-3-3-6 1T
mine dont go up to 12x :S and plus i did prime95 and it had no errors at all! and it has gone to 2255 when i put the FSB down to 205 :S weird stuff. but i get errors when i play games like on source i get "0x2417c1db referenced memory at 0x60b22ed0" aint a clue what that is :S
Guys, this is a Sticky - Overclocking guide for n00bs thread. We aren't supposed to post problems in here, just guide for helping people overclock. You must create new threads in the forum as this thread is very rarely read. Not aimed at anyone, but a Don (admin) is likely to delete all these posts with problems and no guides .
Bubblehead, if you were reading my guide, it was in reference to someone with a AMD A64 San Diego 4000+ processor which has a max CPU multi of 12x. Your processor will not necessarily have this as a limit. Your CPU speed divided by 200 (for an A64) gives you the max multi you have as CPU multi x FSB (aka HTT) = Core speed in mhz. I shall correct my guide, thanks.
Thank god for this guide thanks ! will put it to practice on new setup
Im not sure I should be posting here.... this thread is for Newbies, and Im at least 1 step below that (IDIOT) or maybe even two (AMOEBA) !!!!
Right... the plan is to overclock...
1) Change FSB from 200 --> 240mhz
2) Drop HTT multiplier from 5x to 4x
3) Drop memory speed from 200mhz to 166mhz (to keep actual mem speed at 200mhz)
Is that about right?? I understand that this will keep mem speed in check. What about my PCI / PCI-E busses?? Are they locked or would they be overclocked too (something I dont want!) Also, my raid setup is on sata 3+4 (Native Nvidia onboard). Are they safe?
Obviously I would do memtest before booting and run Prime 95 to check processor would cope.
Any advice would be very much appreciated.
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