Athlon 64, nForce4 and Hypertransport

[congo]

Does anyone know much about the Hypertransport Multiplier and how it affects things in this type of rig?

I read that it should never be set over 1000mhz.

I'm assuming that I should drop the HT multiplier from 5x to 4x when I overclock the FSB to 220mhz, because it automatically drops to 3x (I think, because Everest tells me the HT speed is 660mhz in that scenario).

If I manually set the HT to a 4x multiplier, the setting sticks, is that the correct way to configure it?

Any extra info is greatly appreciated.

[4_Series_Scania]

Hi Congo, For some specialist advice on what you require to know, register & ask here.

Overclockers UK Forums CPU Discussion

These guys have helped me more times than I care to remember, I'm sure you'll find your answers there.

Regards,

Paul.  ;)

[congo]

Thanks Paul,

I did register and looked thru some threads, seems the Hypertransport link doesn't concern the overclocking all that much, but I've got to learn more.


Congo

[Skligmund]

As long as you have no errors (you shouldn't) 4X would be the way to go.

[NicksFXHouse]

Its actually quite simple.... The Hypertransport Mx should remain as close to 1000 (real) as you can get without going over, however, anything over 800 is smoking as long as you have tuned the rest of the system correctly. You should NOT try to go over 1000 if your CPU and memory are properly maxed out as this can blow a system apart, especially RAID0

Unlike the Athlon of the past, the A64 CPU has the northbridge incorporated into it. Therefore, using the system divider for the memory has absolutely no effect on performance as it would with non-A64 processors and it should be used if needed!!!!!!!!!!

The process for PROPERLY overclocking an A64 is different from the Athlon of the past. In a nutshell, here is the process

CPU:
turn off AMD C&Q
1. Drop CPU Hypertransport from 1000 to 200 (1x)
2. Set memory to DDR200 (reduce it to rock bottom for now.. you must remove the memory from the loop by running it well underclocked)
3. Set the vcore (3700+ san diego) MANUALLY to 1.5v (slight increase from the stock 1.4v to find the highest stable FSB)
4. Set multiplier to stock: (3700+ san diego) = 11x
5. Start increasing FSB. This will require you enter the BIOS after each Windows test using a CPU stress test software. There are many available. What you are looking for is 100% stability, with the highest FSB running the STOCK multipier (11x)

Lets say for this example you found that the highest stable CPU speed to be 2700 (2.7g) @ 11x

Next, the memory must be tested for max FSB. In order to do that, we want the CPU out of the loop like we did with the memory above.

With A64... ALWAYS set the memory to 1T CMD. YOU WILL SEE MORE 3D PERFORMANCE WITH 1T ENABLED THAN WITH ANY OTHER MEMORY TWEAK. Your better off running 1T @ 230fsb and tighter timings than running 2T @ 270fsb with loose timings!!!!!!

Mine is at 211fsb @ 1T running the 5:3 divider @ 250x11 CPU
Benchmark Results
RAM Bandwidth Int Buff'd iSSE2 : 6651 MB/s
RAM Bandwidth Float Buff'd iSSE2 : 6606 MB/s
(I am limited by AGP motherboard A8V Deluxe)

Memory:
1. Set the CPU multiplier 4x less than stock (3700+ san diego 11x - 4x = 7x)
2. Leave CPU Hypertransport at 200
3. Set the memory ratio to DDR400
4. Set the FSB to 200 to start (or start where you know the memory is stable.. ex:230, 235... etc)
5. Same as the CPU, increase FSB by 5, boot into windows and run memory stress software untill errrors start to appear. At that point you have a choice... lower fsb, change memory timing or increase Vdd. If your memory is rated for 2.6v, bumping Vdd up to 2.7 or 2.8 is acceptable but lower is better. The most important timing is the CAS rating and the TRAS however raising CAS 2.0 to 2.5 will not hurt performance... CAS 3.0, will. Rasing TRAS 2-3-4clks is also OK.

Once you have found the highest stable FSB with 1T-CMD enabled, your ready to calculate the overclock. Lest say for this example you found the max FSB for the memory to be 250fsb... So the MAX stable CPU speed is 2700 and the MAX stable memory speed is 250

Now that you found the max FSB of your ram and the max speed of your CPU it should be a little easier to clock it together..

Lets say your CPU maxed out at 2700mhz with its default multi of 11x.. But your ram maxes out at 250mhz..

11x 250 = 2750mhz.. That won

[congo]

Thanks Nick N,

This has got to be worth a sticky methinks!

Good info.

[NicksFXHouse]

Thanks Nick N,

This has got to be worth a sticky methinks!

Good info.

Your welcome!

With the older Athlon/Duron/Sempron the system divider can have a negative effect on performance. With the A64, the divider has no effect on performance and will allow the user to significantly enhance the system.

It was easier in terms of testing time to overclock the older processors mainly because the overclock was relative to all components. With the A64 it requires overclocking each system (CPU/Memory) independantly, testing settings for hours, then calculating the final overclock values and testing again. The results far exceed the Athlon of the past since it is not unusual to gain 600mhz+ on a A64 CPU, ESPECIALLY the San Diego core. If you max out the vcore and use extreame cooling... an OC of 800mhz+ is very possible.

A64 systems respond to the 1T CMD memory setting with close to TWICE the performance gain of previous processors. That is why it is best to either select memory rated for 1T-CMD or set the 1T-CMD and work out the memory timing/FSB/vdd based on that being enabled, even if the memory is not 1T rated.

I do alot of video editing and use 2 1G sticks of OCZ 2.0-3-2-5: 2T memory rated at 2.5v. By raising CAS to 2.5 and running 3-3-8 (or 11) with a vdd of 2.7v and the divider of 5:3 (DDR333) I can run the 1T-CMD stable up to 260FSB CPU with a Vcore of 1.65v (216mhz memory), which nets over 7000 in memory scores. When I push the system like that I drop hypertransport in the BIOS to 600mhz, which nets an HTT overclocked rating of around 845mhz.

With that overclock I am well over $1000 dollar FX57 performance using a $245.00 CPU.

The reduced 845mhz OC/HTT will not have any negative influence on performance, at all.

1000 is the target value you do not want to go over but as long as it is over 700-800 and the rest of the system is correctly overclocked... your system is smokin!!!!!!!!

[NicksFXHouse]

PS:

With A64 I have found that memory will run excessive FSB in DOS and will not run anywhere near the the DOS FSB in Windows so I skip the DOS Memtest and do all the stress testing in Windows to save time.


Although memory testing software such as Memtest is good... the real test with A64 is in Windows. I use memtest to find the highest transfer rate based on the memory timings/FSB but all memory stress tests are performed in Windows using software such as Super-Pi 1.4 and OCCT and 3Dmark03-05. Once all that passes the last test for the entire overclock is done using Prime95 for 6-8 hours.

A64 can sometimes throw false errors after 15-20 hours of Prime95 so 8-10 hours without errors says you are OK. Temps must be monitored but with the E-shutdown system A64 processors are very safe compared to the Athlon of the past. I like to keep my Vcore set so my max temp is 50-51c however that is a bit overkill since they can easily hit and run constantly @ 60c without any damage or loss of lifetime use.

Round off errors in Prime95 shortly after starting the test is caused by low Vcore. Some motherboards cannot run AMD C&Q without throwing a round-off error in Prime95 shortly after starting the test. In those cases AMD C&Q cannot be used if disabling C&Q, raising the Vcore, and re-enabling C&Q does not correct the round-off error.

[congo]

I've never tried Cool & Quiet or anything automatic, but I was going to try it just to test it out.

A lot of great info there Nick, I learned more from those few posts than I have looking around the overclock forums for years, I never seem to read

[NicksFXHouse]

Most overclocking sites are designed to cater to the insanity of squeezing every electron of performance out of a system. In that aspect it is a hobby of maximum speed, just like auto racing. In order to accomplish the goals it requires an intimate understanding of modern electronics and the enthusiasts of the hobby take it to levels that make explanations complicated and long winded, just as a Doctor can make a simple ailment sound like the end of the world. LOL!!

There is a difference between performance tuning and the insanity of total system overclocking. In either case one must have an understanding of basic electronic theories and the thermal transfer characteristics of all components, even the small IC

[NicksFXHouse]

The most important starting point is the BIOS. Finding out which BIOS is most stable for the purpose of overclocking, which ones are known for issues and what the issues are. Asus is well known for releasing a motherboard before it has been fully tested and fixing the problems in BIOS releases. Reviewing the forums for BIOS upgrade/downgrade information is the one of the most critical steps allot of people skip and as you have found out it can also be a headache. One of the reasons I selected the A8V Deluxe was because of the BIOS/stability research I did prior to the purchase. I considered upgrading to a PCI Express video card and SLI system but after reviewing several motherboard selections I found that the expense may not provide the results I was after, so since I already had an AGP-ATI X800 AIW I elected to stay with an AGP board for that purchase. I will probably make the PCI-E plunge after the next round of cards/motherboards have proven themselves for at least 9-12 months on the market. I very rarely purchase a motherboard or card that has been on the market for less than a year as I do not wish to be the research and development department for thier products.

Not to post a long winded techno-head answer, but in response to your questions the bottom line is:

1. If you intend to "truly" overclock, in every sense of the word, liquid cooling is a must for ALL CPU/GPU components, period. Heatspreaders are also required for the memory.

2. If you intend to performance tune, there will be limits to how far you can go

[NicksFXHouse]

This page may be a good start for your quest of A8N SLI Information:

http://forums.pcper.com/showthread.php?p=2530698#post2530698

[NicksFXHouse]

These may also help:


http://www.overclock.net/faqs/31782-how ... ts-my.html

http://www.overclock.net/faqs/38169-asu ... ction.html

[congo]

Wow! Thanks

[NicksFXHouse]

Wow! Thanks

To wrap it up