Are all s939 athlon 64 using a 1000HT bus?

[Blahvamp]

Hi I'm lookig to buy an K8NF-9 from gigbyte but i noticed a funny thing :it only supports an 800mhz HT bus. I wondered what does the ht bus change regarding to the upgrade possibilities? I know the nforce3 150 used a 600ht but and though it was a little slower, you could still throw any a64 at it....

 

[T2k]

That's a typo. Even NF3-250-based Gigas run on 1GHz HT, as 939s require.

 

[Phantom69]

Actually it is only 4xHTT (800MHz). The first two revisions (A01, A02) of the nF4 are only capable of a 4xHTT bus. This is why Gigabyte describe the K8NF-9 as having a 'nForce4 4x chipset'.

http://uk.giga-byte.com/MotherBoard/Products/Products_Spec_GA-K8NF-9.htm

revision A03 has 5xHTT (1GHz) support, and is a requirement for all S939 Ultra/SLI boards but not for the S939/S754 nf4 'plain' boards. This is also why the majority of boards available at the moment are non ultra/SLI boards as they are using the earlier revisions of the nf4. Manufacturers are still trying to get upto speed on manufacturing the newer boards.

The FoxConn NF4K8MA-KS is another 4xHTT only S939 board that has been available for a while.

The S939 A64's work perfectly well on a 4xHTT system, it may even allow further overclocking capabilities, as I have knocked my A8N-SLI down to 4xHTT to boost stability with higher overclocks.

HTH

P69

 

[Blahvamp]

Thanks for the input guys.

So this means that the processor either does not get it's speed from the HT bus speed or is it that the processor has it's speed hardcoded in the chip and it sets itself to the right mutiplier accordingly to the Ht bus?

 

[Tim]

Thanks for the input guys.

So this means that the processor either does not get it's speed from the HT bus speed or is it that the processor has it's speed hardcoded in the chip and it sets itself to the right mutiplier accordingly to the Ht bus?

The CPU runs at a multiplier of the base clock not the HT-clock. The stock base clock is 200MHz the HT-connection runs at x5 (or x4) the base clock and the CPU runs at 9-13x of base clock depending on the speed grade (1.8-2.6GHz).

 

[Phantom69]

Thanks for the input guys.

So this means that the processor either does not get it's speed from the HT bus speed or is it that the processor has it's speed hardcoded in the chip and it sets itself to the right mutiplier accordingly to the Ht bus?

The maximum multipler is hard-coded into the CPU, e.g. a S939 3200+ has a 10x multipler (you can lower it, but you can't raise it), so it is 10x the memory frequency which is normally 200MHz = 2000MHz = 2GHz. The HTT bus gets it's speed from applying the HTT multipler to the memory frequency too, so a board with a maximum HTT multiplier of 4x will have a HTT bus speed of 4x200MHz = 800MHz.
Clearly from an overclocking point-of-view this is an excellent arrangement, you can whack the memory speed up to as high as it'll take it, and reduce both the CPU & HTT multiplers to ensure they still stay at sensible frequencies.

For example:
Original config: A64@2GHz (10x200), RAM@200MHz, HTT@1GHz (5x200)
Enhanced config: A64@2GHz (8x250), RAM@250MHz, HTT@1GHz (4x250)
Obviously you don't have to reduce the CPU multiplier that much if you want to overclock the CPU, but in the above config you are technically still running everything at stock/stable speeds except the RAM (unless you've got PC4000). RAM speed is the key, I've seen PC4800 for sale in a few places which surely must be a great system booster! The HTT bus is usually the first to lose stability when overclocking IMHO, so reducing the multipler is recommended to keep it at sensible levels.

HTH

P69

 

[Tim]

The maximum multipler is hard-coded into the CPU, e.g. a S939 3200+ has a 10x multipler (you can lower it, but you can't raise it), so it is 10x the memory frequency which is normally 200MHz = 2000MHz = 2GHz.

This is actually not true, the memory speed is derived from the CPU speed not the other way around. A 2GHz A64 runs at 10x the base clock and DDR400 memory would run at /10 the CPU speed so with DDR400 memory speed = base clock, but if you used DDR333 instead the baseclock would stil be 200MHz the CPU would still run at 10x200MHz=2GHz but the memory would run at 2GHz/12=166MHz.

With a 2.2GHz A64 DDR333 memory would actually only run at 157MHz (DDR314).

 

[epicstruggle]

wow, some really good info in this thread. Thanks tim, phantom.

epic

 

[Phantom69]

The maximum multipler is hard-coded into the CPU, e.g. a S939 3200+ has a 10x multipler (you can lower it, but you can't raise it), so it is 10x the memory frequency which is normally 200MHz = 2000MHz = 2GHz.

This is actually not true, the memory speed is derived from the CPU speed not the other way around. A 2GHz A64 runs at 10x the base clock and DDR400 memory would run at /10 the CPU speed so with DDR400 memory speed = base clock, but if you used DDR333 instead the baseclock would stil be 200MHz the CPU would still run at 10x200MHz=2GHz but the memory would run at 2GHz/12=166MHz.

With a 2.2GHz A64 DDR333 memory would actually only run at 157MHz (DDR314).

Ahem, ah yes, I might have got that wrong...
I had forgotten that pretty much every frequency in an A64 system is separate (and theoretically locked) from all the others including the RAM...Even better for overclocking!

Don't you just hate people that post bad information?

P69

 

[T2k]

Actually it is only 4xHTT (800MHz). The first two revisions (A01, A02) of the nF4 are only capable of a 4xHTT bus. This is why Gigabyte describe the K8NF-9 as having a 'nForce4 4x chipset'.

http://uk.giga-byte.com/MotherBoard/Products/Products_Spec_GA-K8NF-9.htm

revision A03 has 5xHTT (1GHz) support, and is a requirement for all S939 Ultra/SLI boards but not for the S939/S754 nf4 'plain' boards. This is also why the majority of boards available at the moment are non ultra/SLI boards as they are using the earlier revisions of the nf4. Manufacturers are still trying to get upto speed on manufacturing the newer boards.

The FoxConn NF4K8MA-KS is another 4xHTT only S939 board that has been available for a while.

Really? That's a shame. :?

Another typical example how f*cked up this 'time-to-market-is-everything' stupidity at Nvidia.

The S939 A64's work perfectly well on a 4xHTT system, it may even allow further overclocking capabilities, as I have knocked my A8N-SLI down to 4xHTT to boost stability with higher overclocks.

HTH

P69

Sure, if you wanna OC on other systems, first thing you should do is put HT back 4x to have overhead to OC up to 250MHz at least.

 

[fO Che -USA-]

Ok so I have a question if I am not overclocking should I run my K8N NEO2 and 3200+ at 5x HT, the options is in the bios but i thought A64 only ran at 800mhz HT. Second question how does a FX have 1600mhz HT I dont get it. sorry for the total noob question

 

[Phantom69]

Ok so I have a question if I am not overclocking should I run my K8N NEO2 and 3200+ at 5x HT, the options is in the bios but i thought A64 only ran at 800mhz HT. Second question how does a FX have 1600mhz HT I dont get it. sorry for the total noob question

Socket 754 A64's only have an 800MHz HT, whereas S939 A64's (except for the S939 3400+ which was only for OEMs) can take a 1000MHz HT, so if you have a Socket 939 based motherboard, such as the K8N Neo2, then yes you can run 5x on the HT bus if you aren't overclocking.

The HT bus is sometimes quoted as double that mentioned above (because it is bi-directional), so an 800MHz HT bus is quoted as 1600MHz, and 1000MHz HT bus as 2000MHz. This is probably where you saw the FX figure quoted, although all the FX chips are Socket939 and hence capable of 1000MHz (or 2000Mhz).

See here for a good table of the chip variants:

http://www.c627627.com/AMD/Athlon64/

HTH

P69