zakelwe
07-07-2005, 12:09 AM
If you want to benchmark your card at full speed make note of unwinders comments here
http://www.beyond3d.com/forum/viewtopic.php?t=24615&postdays=0&postorder=asc&start=60
Some updated info about investigation progress:
--------------------------------------
1) G70 has 3 independently clocked domains with no doubts. I've already fully ripped clock detection logic from the driver, so new RT will replace single "Core clock" graph with 3 graphs, representing current clocks of each domain. I still have no strict info about the functional purpose of these domains, most likely they are geometric domain (that clock is currently read by publicly available RT and 3DMark), shader domain and ROP domain. So this naming scheme ("Core clock \ geometric domain", "Core clock \ shader domain" and "Core clock \ ROP domain") is currently used in beta of RT 15.7. However we're still waiting for NV's official comments on it, as well as performing own synthetic testing allowing us to determine domain functional purposes ourselves. So domain naming scheme will probably change in future.
2) Shader/ROP domain are clocked with more primitive PLL comparing to geometric domain allowing per-1MHz clock frequency adjustment, and currently NVIDIA driver is able to adjust clocks of these domains with 27MHz (oscillator frequency) step only. For example, default 430MHz ROP clock is generated as 27MHz * 16, and the next ROP clock the driver is able to set is 459MHz (27MHz * 17). This results in rather interesting effect when overclocking G70: often overclocking will adjust geometric domain clock only, e.g. attempt to set 440MHz instead of default 430MHz will result in generating the same 432MHz for ROP domian clock, but 480MHz (440+40) for geometric domain clock. This effect is clearly visible on new RT's core clock monitor, G70 owners may also verify it with fillrate tests and see that there are no changes in fillrate for such example.
3) Target 3D clock for shader/ROP domain (430MHz) and delta for geometric domain clock (40MHz) are explicitly specified in VGA BIOS in performance table. New RT is able to display this delta in "NVIDIA VGA BIOS information" section of the diagnostic report. The example of such info is shown below:
$ffffffffff ---------------------------------------------------
$ffffffffff NVIDIA VGA BIOS information
$ffffffffff ---------------------------------------------------
$1100000000 Title : GeForce 7800 GTX VGA BIOS
$1100000002 Version : 5.70.02.11.01
$1100000100 BIT version : 1.00
$1100000200 Core clock : 275MHz
$1100000201 Memory clock : 1200MHz
$1100010000 Perf. level 0 : 275MHz/600MHz/1.20V/100%
$1100010001 Perf. level 1 : 415(+35)MHz/600MHz/1.40V/100%
$1100010002 Perf. level 2 : 430(+40)MHz/600MHz/1.40V/100%
$1100020000 VID bitmask : 00000011b
$1100020100 Voltage level 0 : 1.20V, VID 00000000b
$1100020101 Voltage level 1 : 1.30V, VID 00000010b
$1100020102 Voltage level 2 : 1.40V, VID 00000001b
Please pay attention to performance level 1 descriptor. It is so called low power 3D perormance level, and the system uses this performance level as a temporary step when switching from 3D (performance level 2) to 2D (performance level 0). As you see, it has different "Geometric clock delta", and it perfectly matches with temporary 450MHz clock (415+35), which you can see on many clock graphs.
During overclocking the driver uses this BIOS-defined delta and generates closest possible to desired clock for ROP/shader domain and closest possible to (desired clock + delta) for geometric domain. => We'll probably see some BIOS editors in the future, allowing us to alter this delta. Or even independent clock control sliders for each domain (of course, if NV will decide to provide such functionality in their driver).
4) Digit-Life are currently preparing the review summing all this info.
5) Unfortunately I'm leaving the city for vacation soon, so I'll be probably offline since 11th July till 8th of August. So new RT will be publicly launched when I'll return.
Stay tuned
-------------------------------
This means that unless you reach a multiple of 27Mhz you will not be overclocking the ROP or shader domain, just the geometric domain, so your benchmark scores will not be as good as possible until you reach the next multiplier level.
To test this can someone with a 7800 bench 3dmark03 GT4 nature at 435, 445, 455 and 465 ? The increase should not be linear but spike at 465Mhz when the ROP and shader domains raise to the next level.
Regards
Andy
http://www.beyond3d.com/forum/viewtopic.php?t=24615&postdays=0&postorder=asc&start=60
Some updated info about investigation progress:
--------------------------------------
1) G70 has 3 independently clocked domains with no doubts. I've already fully ripped clock detection logic from the driver, so new RT will replace single "Core clock" graph with 3 graphs, representing current clocks of each domain. I still have no strict info about the functional purpose of these domains, most likely they are geometric domain (that clock is currently read by publicly available RT and 3DMark), shader domain and ROP domain. So this naming scheme ("Core clock \ geometric domain", "Core clock \ shader domain" and "Core clock \ ROP domain") is currently used in beta of RT 15.7. However we're still waiting for NV's official comments on it, as well as performing own synthetic testing allowing us to determine domain functional purposes ourselves. So domain naming scheme will probably change in future.
2) Shader/ROP domain are clocked with more primitive PLL comparing to geometric domain allowing per-1MHz clock frequency adjustment, and currently NVIDIA driver is able to adjust clocks of these domains with 27MHz (oscillator frequency) step only. For example, default 430MHz ROP clock is generated as 27MHz * 16, and the next ROP clock the driver is able to set is 459MHz (27MHz * 17). This results in rather interesting effect when overclocking G70: often overclocking will adjust geometric domain clock only, e.g. attempt to set 440MHz instead of default 430MHz will result in generating the same 432MHz for ROP domian clock, but 480MHz (440+40) for geometric domain clock. This effect is clearly visible on new RT's core clock monitor, G70 owners may also verify it with fillrate tests and see that there are no changes in fillrate for such example.
3) Target 3D clock for shader/ROP domain (430MHz) and delta for geometric domain clock (40MHz) are explicitly specified in VGA BIOS in performance table. New RT is able to display this delta in "NVIDIA VGA BIOS information" section of the diagnostic report. The example of such info is shown below:
$ffffffffff ---------------------------------------------------
$ffffffffff NVIDIA VGA BIOS information
$ffffffffff ---------------------------------------------------
$1100000000 Title : GeForce 7800 GTX VGA BIOS
$1100000002 Version : 5.70.02.11.01
$1100000100 BIT version : 1.00
$1100000200 Core clock : 275MHz
$1100000201 Memory clock : 1200MHz
$1100010000 Perf. level 0 : 275MHz/600MHz/1.20V/100%
$1100010001 Perf. level 1 : 415(+35)MHz/600MHz/1.40V/100%
$1100010002 Perf. level 2 : 430(+40)MHz/600MHz/1.40V/100%
$1100020000 VID bitmask : 00000011b
$1100020100 Voltage level 0 : 1.20V, VID 00000000b
$1100020101 Voltage level 1 : 1.30V, VID 00000010b
$1100020102 Voltage level 2 : 1.40V, VID 00000001b
Please pay attention to performance level 1 descriptor. It is so called low power 3D perormance level, and the system uses this performance level as a temporary step when switching from 3D (performance level 2) to 2D (performance level 0). As you see, it has different "Geometric clock delta", and it perfectly matches with temporary 450MHz clock (415+35), which you can see on many clock graphs.
During overclocking the driver uses this BIOS-defined delta and generates closest possible to desired clock for ROP/shader domain and closest possible to (desired clock + delta) for geometric domain. => We'll probably see some BIOS editors in the future, allowing us to alter this delta. Or even independent clock control sliders for each domain (of course, if NV will decide to provide such functionality in their driver).
4) Digit-Life are currently preparing the review summing all this info.
5) Unfortunately I'm leaving the city for vacation soon, so I'll be probably offline since 11th July till 8th of August. So new RT will be publicly launched when I'll return.
Stay tuned
-------------------------------
This means that unless you reach a multiple of 27Mhz you will not be overclocking the ROP or shader domain, just the geometric domain, so your benchmark scores will not be as good as possible until you reach the next multiplier level.
To test this can someone with a 7800 bench 3dmark03 GT4 nature at 435, 445, 455 and 465 ? The increase should not be linear but spike at 465Mhz when the ROP and shader domains raise to the next level.
Regards
Andy