Newbie Overclocker Questions

[LuckeeDogg]

Hi,

I'm not new at building or using computers, but as far as overclocking goes I admit to having limited experience. I am familiar, but I've never really been hardcore into it. I have a few questions. (See sig for system specs)

1.) What are the actual benifits of running an unlocked CPU

2.) I've unlocked my CPU, and from what I can tell I was succesful. I have access to all the multipliers and when changed in the BIOS it shows up with the proper speed (XP1500, XP1600...etc.) The odd thing is that when I set the BIOS to use default CPU ratio, the BIOS reports the CPU as an XP1900+ instead of a 2000+. Upon looking at the multipliers, I have no 12.5 which is what the XP2000 uses. Also, setting the multiplier manually to 13x shows the CPU speed as it should be with a 12.5x. Also strange is the fact that if I set the multiplier to 14x, the BIOS and Windows reports it as only 667MHz at 133 FSB. Can you not set the multiplier HIGHER than what the CPU's default multiplier is??

3.) Overclocking just the FSB with the CPU set at its correctly reported speed, I cannot squeeze a single MHz over 150...I'm aware that I need to increase the core voltage as well, everything up to the max allowable was tried. At 150MHz,1.85V...the system POSTs fine and Windows loads without a hitch. Set it to 151 or above, the systems POSTs fine but Windows won't even begin to load. I've tried this with VERY relaxed RAM timings. Is my memory holding me back?? Its Corsair XMS 2400 (which is rated at 300MHz)...150x150=300MHz DDR. It just seems odd that it craps out at EXACTLY the rated speed. But I guess it's possible.

Thank you in advance for any replies.

LD


No sig showing up ? :( Anyway...here are my system specs :

---------------------------------------

Windows XP Pro (SP1 and all subsequent updates)
SOYO Dragon Plus (4 in 1 v4.43)
Athlon XP 2000+ (AGOIA "Y")
Corsair XMS2400 DDR 512mb (single module-bank 1)
GeForce 2 GTS
Maxtor 40 GB 7200rpm ATA100 HDD
Philips 20X10X40 CD/RW-master
Acer 16X DVD-ROM-slave
Onboard RAID-disabled
Onboard LAN-disabled
Onboard Sound-enabled
DSI/Broadxent 56k V.92 Fax Modem
Antec 1040B server case (400w PS) modded...
(3 intake, 3 exhaust fans)
Volcano 7 CPU cooler
CPU Temp (full load): 36-38c
CPU Temp (idle): 28-30c

[AlexGee]

This goes beyond my experience. Sounds like the MOBO is not up to job of dealing with the speed alterations. I never unlocked an Athlon but have Overclocked mine from a 2000+ to a 2100+, almost 2200+ using only FSB.

Question:When set to 150 what multiplier is in effect and what speed does BIOS report for CPU? I think you would be lucky to get more than 1800 mhz. out of any given Athlon. Mine falkes out at just about exacty 1800, this may well be the limit for our XP core without extreme cooling. This is why, I think, the current core is only sold up to 2200 - there just isn't much more in there. PPL getting more than that are probably using water coolers. The 2400 and 2600 is enterly new core.

To test the memory you could set the multiplier to the low side, like say 12x, or 11x, THEN pump the FSB above 150 and see what happens. AGP is getting a boost too and I don't know if your board has a workable fraction to give the AGP card at above 150.

I think people who unlock the CPU are often setting multiplier LOWER than the rated speed ao that they can pump the FSB to the max without overheating CPU. This way the RAM runs much faster and 1800 mhz benchs higher than a typical 1800, even though CPU is running same speed RAM is going faster. With your RAM maybe you could do same.

[LuckeeDogg]

Thanks for responding,

I can set the multilplier to anything and 150MHz FSB seems to be the limit, even if i set the multiplier very low. The system runs perfectly stable at 12.5 multiplier and 150MHz FSB which is 1875 MHz with the Vcore bumped up to 1.85v. If I go 1 MHz more to 151...system posts but Windows wont load.

You're right, it may be a board limitation as I know for a fact that it does not support the 1/5 PCI divider

LD

[jmichna]

I'm not familiar with your mobo, and what tweaks you can employ, but to get 150mHz fsb out of DDR2400 ram is pretty good... what are your specific timings for the ram e.g., bank interleave, precharge-to-active, active-to-precharge, active-to-command, DRAM burst, fast R-W, etc., etc. If you are real aggressive in your settings, you can back off a bit and try raising the bus speed higher.

You have to test your mem throughput, though, to find out what balance of "detuning" ram settings but increasing bus speed actually yields the best ram performance. Iy takes a good while to find that sweet spot. For myself, I set my ram settings as aggressively as possible and just see how far I can push the bus speed.

Does your mobo permit you to adjust the vdimm... if so bump up from default 2.50 to 2.70... even 2.80 if you have good case cooling.

Although I didn't check, I assume your mobo is a KT333 chipset, which defaults to running asynchronously: 133mHz fsb and 166mHz mem bus. If this is true, and also assuming you have a 1/5 divider that kicks in when your bus is set to 166mHz or higher, then here is how unlocking helps:

With a KT333, transferring data (asynchronously) between the two different bus speeds takes a wee bit of "translation" time... if you can run both at the synchronously -- same speed (166mHz and faster) you don't have this lag moving the data between the buses. So, for example with my unlocked XP2100+, I can lower my cpu multiplier to 10.5, raise the fsb to 166 and still be at stock speed... but now my fsb and mem bus are synchronous. Next, I bump up (both) bus speeds and get automatic cpu speed increase, as well as speeded up the memory, pci and agp speeds... everything is faster.

Once I know what the bus (pci and agp devices) and memory can tolerate, now I'll go back and see if I can get another 0.5 multiple out of my cpu. For example, I'm currently running at 10.5, at 173 bus speed. My cpu is 1.775vcore, and my DDR3200 C2 ram is at 2.80vdimm. All my memory timing are very agressive. I'm running at better than XP2200+ speed. I have boosted my multiplier to 11.0 but I had to crank up the vcore to 1.80 and I really don't like to do that for day-to-day, at least until it gets colder around here.

I should be able to run at 1.85vcore without damaging the cpu, and probably 2.90vdimm... once the room gets colder.

See the attached screen capture for details.
jmichna

[AlexGee]

I see. Well, sorry I don't have more help, but I must say, 1875 ain't bad! Good work. Maybe I could get the same with a Volcano, I got a Compusa copper sink, probably ****.

[LuckeeDogg]

jmichna:


Actually its a KT266A chipset. I 'm not sure right off the top of my head what the exact mem timings are. I do know they are very aggressive, But lowering the timings to extrememly modest settings has no effect. Its set aggressively at 150 MHz FSB, the system boots fine and everything is stable within windows. I go to 151 MHz with VERY relaxed memory timings and the system POSTs, but windows won't even start to boot. As far as adjusting the RAM voltages...can't do it on this board :mad: Maybe I should just be happy with 1875 MHz, 12.5@150 FSB if everything is stable. I'll probably be building another system very soon so I guess I'll just have to pay a little closer attention to the overclockability of the board. :rolleyes: Thank you for your very detailed information. It was very helpful.

LD

[jmichna]

Originally posted by LuckeeDogg
jmichna:
....Maybe I should just be happy with 1875 MHz, 12.5@150 FSB if everything is stable. I'll probably be building another system very soon so I guess I'll just have to pay a little closer attention to the overclockability of the board. :rolleyes: Thank you for your very detailed information. It was very helpful.

LD LuckeeDogg ....
Thank you for the compliment :-@

Don't forget, you are doing real well to get 150fsb with DDR2400 ram!!!

I'm waiting for the KT400As to start rolling out... should be right around the time the XP2700+ (native166 fsb) and higher start to roll out. Hang on for just a couple more months... need the time to start hiding money from my wife anyway :p

EDIT: Plus, I hope/expect the KT400A will have the 1/6 divider!

[LuckeeDogg]

LOL

I'll have to do the same with my wife :)

I do have an update however. It seems that if I disable the option in my BIOS "Auto Detect DIMM/PCI Clock", I AM able to push the FSB higher than 150 if I lower the multiplier. It somehow seems related th the CPU speed, though. Example...if I go lower with the multiplier I can go higher with the FSB ( the max I've been able to get was 159). But no matter what combination i use, the system seems to **** out when the CPU frequency reaches around 1875-1888 MHz . Either my RAM is holding me back from getting more...or that is just the limitation of overclockability of my CPU.

Plus, I hope/expect the KT400A will have the 1/6 divider!

From what I've read, some boards....specifically the new ABIT board, have the clock generator that support this and the funtion within the BIOS. But the KT400 chipset does not.


Regards,

LD

[Bigjakkstaffa]

Ive been rading up on the Kt400 myself and its not wotrth the money - i too however am eagerly awaiting the Kt400A's...i hope they turn out better :)

--Jakk:t

[jmichna]

KT400 = NO 1/6

KT400A = 1/6

[BJUK]

Hi
Iam no expert but i was told i had to lower the multplyer to 10x and up the fsb as high as it will go hopefuly 166 this should give better performance if i understood it corectly.

:t :t

[Bigjakkstaffa]

Hgher FSB increases the performance of all the devices in the system as they are runnng faster than they should, multiplier overclock is only overclocking the CPU

Therefore it is better to have a higher FSB o/c than multiplier, for this reason when a chip beciomes unstable at a certain speed, people lower their mutliplier and increase the FSB to reach that same speeed, althouhg the CPU hasnt been overclocked furthur, the raised FSB means the system as a whole is running faster

--Jakk:t

[jmichna]

Originally posted by LuckeeDogg
....Either my RAM is holding me back from getting more...or that is just the limitation of overclockability of my CPU.LuckeeDogg...
If you want to convince yourself which is the limitation, lower your cpu multiplier to something much lower, like 7.5 or 8.0, then push your bus speed to that 159mHz you've reached before... if all A-OK... then push the bus speed higher... your cpu speed won't be the limiting factor... your ram and/or all your pci/agp bus devices will begin to malfunction at some bus speed. Back off 1 mHz from there. You now know what the ram and devices will take. The goal here is to find out just what the bus speed limit is.

Let's assume you've tried the above and find you can push things to 163mHz. Now raise your cpu muliplier to the closest value that will yield --- at your new bus speed --- a cpu speed you know you've achieved, something between 1875 and 1888.

For example: 1875/163 = 11.50, and 1888/163 = 11.58
Set your cpu mulitplier to 11.5

Run some demanding applications, 3D2001se, Seti@home, etc. to check for stability, temperatures.

You might find you need better cpu cooling, better case cooling, better chipset cooling, faster ram, etc.
jmichna

[LuckeeDogg]

J

After playing around quite a bit, I think I have determined that it IS actually my RAM bombing out. Even if I use a low multiplier with a higher FSB speed, I can't seem to approach the max CPU speed without my system either failing to boot at all or running stably as I can with a higher multy and a lower FSB. So that is most likely telling me that the RAM has hit the wall as far as performance goes. This is correct ???

LD

[Bigjakkstaffa]

Corsair is amongst the top RAM manufacturers, and the stuff you've got should run 266FSB no sweat...

Personally i think, lookign at the problems you described with the speed detection in the initial post its your motherboard

See if there are any BIOS flashes out there adressing any such issues

--Jakk:t

[jmichna]

Originally posted by Bigjakkstaffa
Corsair is amongst the top RAM manufacturers, and the stuff you've got should run 266FSB no sweat...

Personally i think, lookign at the problems you described with the speed detection in the initial post its your motherboard

See if there are any BIOS flashes out there adressing any such issues

--Jakk:t BJ...
I think you misunderstand the situation. He has surpassed 266mHz (133mHz x DDR = 266mHz). He's running at 159mHz which would yield "318mHz DDR," beyond default DDR2400 (300mHz rated).
jmichna :t

[jmichna]

Originally posted by LuckeeDogg
J

...So that is most likely telling me that the RAM has hit the wall as far as performance goes. This is correct ???

LD LD...
With your testing, still don't with absolute certainty if it's devices or ram... it probably is the ram. That would be my conclusion. Unless your board lets you increase the vdimm, you're not likely to get any higher.

If you really wanted to put in the effort to see if it is hardware, not ram, then pull out the sound and NIC, etc., leaving only ram, vid card and cpu. Same as before, lower the cpu multiplier to make sure the cpu is not the limiting factor, then push the bus speed once again. After a while, it gets to be more trouble and effort than saving/buying faster ram.

One last consideration is chipset cooling, but if you issues appear at boot or shortly after boot, then it's not likely chipset overheat since the pc hasn't been running for very long to result in overheating the chipset north bridge/southbridge (northbridge is usually the hotter one).
jmichna

[LuckeeDogg]

J

Tried isloating by removing/disabling all uneccessary harware. Still the same situation. Seems like the RAM is bombing out. Even with a lower multy....say 10x....and a FSB of 159 (which seems to be the max I can acheive), which would only equate to a CPU speed of 1590. Even in this situation, I can boot into Windows....evrything seems somewhat stable ( no lockups, crashes...etc) when running general apps. But when hardcore crunching using SETI, Prime95...etc, it seems as though it is not 100% stable. Prime95, for example, dumps about 5-10 miutes into it with a hardware failure error. As far as cooling goes, I don't really think this is an issue. Using a default, or only slightly overclocked setup, I can run a stress test app like Prime 95 for hours and my CPU temps max out about 38-40c, and my general case temp is much lower than that.

At the time I built this rig, Corsair was only up to XMS2700...but I opted for the XMS2400 thinking I wouldn't really be pushing it to hard anyway.....20/20 hindsight :rolleyes:

Oh well...if I can acheive 1800-1875 MHz with a higher multiplier and lower FSB and remain stable, I will be happy.....for now.....or at least until the next project which I will definately be going "balls to the wall" :D


LD :)

[lptech]

If you need a good reference book for overclocking then I would recommend the following book:

PC Overclocking, Optimization & Tuning - 2nd Edition
by Victor Rudometov and Eugene Rudometov
Published by Charles River Media
ISBN: 1931769052

It should give you plenty of background on the how-to's of overclocking your CPU! Good luck!:)

[x51out]

If I may insert a suggestion. My Shuttle Ak31v2.0/KT266 mobo has active cooling on the northbridge as do all motherboards nowadays, KT266A and above. The problem was that I couldn't get the fsb higher than 138. I can now get it to 158 easily. The solution: the hsf on the northbridge was glued on (besides two pins). After removing the goo and applying some REAL magically delicious arctic silver... well, 20 mhz increase ain't too shabby for PC2100 and a now "ancient" board...;) .

[cuebreakerz]

i also have a soyo dragon plus kt266a xp2000
default it runs at 1200mhz.
fsb was set at 100/133 so i put it x2-133 fsb i didnt change anything else. rebooted and it then read as an xp2000
it now runs at 1700mhz. which is fine for me i have never over clocked before and had no clue what i was doing when i changed it.this bios thing has me messed up.this board also has a cpu ratio with all kind of settings so i left it alone it also has this turbo mode and normal mode i left that alone to it said in turb windows may not be stable lol so i havent tuched ****.
cpu temp 45
mb30.
its a great board couldnt ask for anything better:)

[x51out]

Xp2000+ runs at 12.5x133 (266 ddr)=1666mhz default. Dude, the BIOS is your friend. BIOS defaults are usually very conservative, but not performance oriented. Great board you have. There are numerous sites explaining bios settings, try this one on for size:BIOS GUIDE (http://www.adriansrojakpot.com/Speed_Demonz/New_BIOS_Guide/Index.htm)
Good Luck!:t

[LuckeeDogg]

cuebreakerz....

Good article x51out posted....

Also, MSNY over at amdmb.com posted a good guide specifically for setting up Dragon Plus boards...including memory timings.

Heres the link to that article:

http://www.amdforums.com/showthread.php?s=&threadid=116775


LD :t

[Giblet Plus!]

Lucky Dogg- I think both your memory (or motherboard) and cpu are holding you back. All Paliminos can't overclock past about 1900 mhz even with 1.85V and air cooling.

check out the cpu database at

www.overclockers.com

I'd make sure that your chipset heatsink is on really good - maybe put some of your own thermal paste and a fan on.

If that doesn't work, your ram's holding you back. Try giving the ram some more voltage to see if it OCs better that way. That doesn't always work - my year old ddr2100 can't stand anything over 2.6V.

You have quite a respectible overclock for an xp2000 on air anyways. I leave my xp2000 at 1820 mhz and 1.775 V for stability. I'll go farther when I get watercooling in a few months. :)

[LuckeeDogg]

Thanks for your reply :)

The only bummer is, with my board (SOYO Dragon Plus), I can't adjust the ram voltages. i think if I could, I might be able to sqeeze a bit more out. As far as the HSF...Its on solid, with Artic Silver 3....also the northbridge comes factory with nothing between the chip and the heatsink....so I also put AS3 on that also...hasn't really helped much though. The good thing is...even overclocked to 1875 @1.85v, the temps stay right around 40c at full load....which from what I can tell is excellent. Like you said...I really can't complain considering that my rig is only air cooled...so I won't :) I'm very happy with my rig and the performance I've gotten with it so far.

Thanks


Regards


LD :t