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Topic Title: What EXACTLY does amd processor driver + dual core optimizer?
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Created On: 11/07/2008 03:14 PM
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 11/08/2008 02:27 PM
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fizzbang
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Well, I got nothing past the descriptions and personal experience. I know for a fact that the dual core optimizer doesn't split single-threaded apps on my PC; they only ever run on one core. Is the game you're testing already multi-threaded? Many are these days. If so, it'll run on both cores regardless of the optimizer.

-------------------------
939Dual-SATA2 v1.05, BIOS v2.31
Opteron 165 (CCBWE 0550UPMW) @2.7GHz, 1.35V
TWINX2048-3200C2PT 2.5-3-3-6 1T
Thermaltake Big Typhoon
ATI X1800GTO
 11/08/2008 02:29 PM
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Adam F
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I have over 32 games and they ALL split evenly over each core.

I use Everest ultimate to test and log the in game temps, Core utilization , memory utilization and so on.

Just dawned on me you may have missed one important factor when running games and 3D apps you need to change multi threading options in drivers from auto to ON. This forces even single threaded apps to multi thread over both cores.

Every last application and game listed I know for a fact shows the the cores are always with in 5 % of each other and NEVER more then 4c of each other tops.



Edited: 11/08/2008 at 02:41 PM by Adam F
 11/08/2008 02:47 PM
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fizzbang
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Interesting. What multi-threading options in which drivers?

-------------------------
939Dual-SATA2 v1.05, BIOS v2.31
Opteron 165 (CCBWE 0550UPMW) @2.7GHz, 1.35V
TWINX2048-3200C2PT 2.5-3-3-6 1T
Thermaltake Big Typhoon
ATI X1800GTO
 11/08/2008 03:46 PM
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Adam F
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 11/08/2008 05:24 PM
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pluto2
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Hmmm... I noticed too that a single threaded app (cpu burn in) acually somehow balances over both cores. You mean this doesn't happen without the optimizer? Gonna have to check that out
 11/08/2008 05:47 PM
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Adam F
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CPU burn in was made to run on 1 core at a time. To get it to run on 2 cores run 2 instances of the burn in at one time.
 11/08/2008 10:07 PM
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fizzbang
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Adam - I don't have an nvidia video card, so I don't have that option. I'm thinking it's that setting in your video driver that's forcing or assisting your games in multi-threading. I doubt it has anything to do with the Dual Core Optimizer.

-------------------------
939Dual-SATA2 v1.05, BIOS v2.31
Opteron 165 (CCBWE 0550UPMW) @2.7GHz, 1.35V
TWINX2048-3200C2PT 2.5-3-3-6 1T
Thermaltake Big Typhoon
ATI X1800GTO
 11/09/2008 12:04 AM
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Adam F
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I don't use dual core optimizer , I use vista lol. But in XP who knows. I still used it and my systems where always rock solid performers.
 11/09/2008 02:40 AM
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ngwayne
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hmm...

Edited: 11/09/2008 at 02:48 AM by ngwayne
 11/09/2008 02:45 AM
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ngwayne
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hi,

I've tested my system again to check if Adam F's theory is workable, and guess what, I cannot spot the difference btwn having DCO or not, so I don't bother to post the screen shot of it at here...

but I guess I have to post tis pic, because with DCO or not I can still adjust thread optimization, because it's a feature of Nvidia card not DCO function



Edited: 11/09/2008 at 03:01 AM by ngwayne
 11/09/2008 04:58 AM
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pluto2
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this all is just strange and I bet we'll never really have an answer. But I'm telling you what, if I can't find ONE SINGLE offical yet burried line about that those 2 things do anything apart from we know for sure, I'm leaving them out of my system. Can't see a point in having them there really.
On the other hand they are part already of vista it seems so I guess having them there won't cause any harm either.

It's annoying though to not be able to find some real answers! Guess the recommendatatino to install these things all this time has just been brought up on what people assume rather than some real documents describing these "hidden things".
 11/09/2008 05:11 AM
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Adam F
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look I for one will do what I have to , to make sure I use both my cores equally full time no matter what. If using XP and I know it wasn't built into the OS like vista. I would then use the optimizer and the driver just to cover all my bases. But each to there own.
 11/09/2008 08:56 AM
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fizzbang
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It would be interesting if someone with XP and an nvidia card would test. I'm with Pluto2 in that without documentation or practical results I'm not going to bother with it.

-------------------------
939Dual-SATA2 v1.05, BIOS v2.31
Opteron 165 (CCBWE 0550UPMW) @2.7GHz, 1.35V
TWINX2048-3200C2PT 2.5-3-3-6 1T
Thermaltake Big Typhoon
ATI X1800GTO
 11/09/2008 02:27 PM
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pluto2
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I can't find either of those, yet anyway. But I still challange anyone to post such as I'm not saying anyone is wrong, but I want facts, not assumptions.
 11/09/2008 08:17 PM
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BigBear
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What is the difference in the Nvidia option of Threaded opt on/auto?
Mine is defaulted to auto.
I asked b/c:
The game Ravenshield (Rainbow Six 3) requires me to use DCO.
If I do not enable DCO (gaming mode) for that game only, it will get stuck in a intro/video loop during loading.
I have older games such has Operation Flashpoint from 2001, that does not need DCO.

OK.........I just tested the Nvidia Threaded Optimization to ON........
RavenShield still got stuck.

-------------------------
ASUS L1N64-SLI 680a WS Dual Socket L, 2x AMD Athlon 64 FX-74, 2x ASUS EN8800GTX/DDR3/768M (SLI),
2x WD 150GB Raptors 10000rpm-Raid0, 4gig Corsair DDR2@800mhz-PC6400, Dell 30in (2560x1600),
Enermax Galaxy 1000W, ThermalTake Armour Extreme, Vista Ultimate-64bit OS...
TrackIR:4 Pro

Edited: 11/09/2008 at 09:05 PM by BigBear
 11/10/2008 05:29 AM
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pluto2
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I have no idea, how does that relate to the current topic?
 11/10/2008 07:00 AM
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BigBear
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Originally posted by: pluto2

I have no idea, how does that relate to the current topic?


I myself, did not want to install DCO on an all Vista64 system.
Adam pointed to Nvidia Threading opt, which made no difference for me, so DCO is still a must have program on my Vista (which everyone claims it's not needed).

-------------------------
ASUS L1N64-SLI 680a WS Dual Socket L, 2x AMD Athlon 64 FX-74, 2x ASUS EN8800GTX/DDR3/768M (SLI),
2x WD 150GB Raptors 10000rpm-Raid0, 4gig Corsair DDR2@800mhz-PC6400, Dell 30in (2560x1600),
Enermax Galaxy 1000W, ThermalTake Armour Extreme, Vista Ultimate-64bit OS...
TrackIR:4 Pro
 11/10/2008 07:22 AM
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pluto2
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This still regards games though. We know that DCO is usable for some games, but outside the gme world there has been absolutely no proof this far as far as I know that it does anything usable. We're still awaiting any proofs, but there seems to be none. DCO = good for some games, processor driver = good for cool and quiet, apart from this, it seems that those 2 don't do a thing. So in my case, music production, it seems I hacv eno use what so ever to install them.
 11/10/2008 09:26 AM
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fizzbang
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Been doing some more reading. This is from a 2005 Microsoft developer's note...

Game Timing and Multicore Processors

By Chuck Walbourn, Software Design Engineer

XNA Developer Connection (XDC)

December 2005
Introduction

With power management technologies becoming more commonplace in today's computers, a commonly-used method to obtain high-resolution CPU timings, the RDTSC instruction, may no longer work as expected. This article suggests a more accurate, reliable solution using the Windows APIs QueryPerformanceCounter and QueryPerformanceFrequency.
Background

Since the introduction of the x86 P5 instruction set, many game developers have made use of read time stamp counter, the RDTSC instruction, to perform high-resolution timing. The Windows multimedia timers are precise enough for sound and video processing, but with frame times of a dozen milliseconds or less, they don't have enough resolution to provide delta-time information. Many games still use a multimedia timer at start-up to establish the frequency of the CPU, and they use that frequency value to scale results from RDTSC to get accurate time. Due to the limitations of RDTSC, the Windows API exposes the more correct way to access this functionality through the routines of QueryPerformanceCounter and QueryPerformanceFrequency.

This use of RDTSC for timing suffers from three fundamental issues:

1. Discontinuous values. Using RDTSC directly assumes that the thread is always running on the same processor. Multiprocessor and dual-core systems do not guarantee synchronization of their cycle counters between cores. This is exacerbated when combined with modern power management technologies that idle and restore various cores at different times, which results in the cores typically being out of synchronization. For an application, this generally results in glitches or in potential crashes as the thread jumps between the processors and gets timing values that result in large deltas, negative deltas, or halted timing.

2. Availability of dedicated hardware. RDTSC locks the timing information that the application requests to the processor's cycle counter. For many years this was the best way to get high-precision timing information, but newer motherboards are now including dedicated timing devices which provide high-resolution timing information without the drawbacks of RDTSC.

3. Variability of the CPU's frequency. The assumption is often made that the frequency of the CPU is fixed for the life of the program. However, with modern power management technologies, this is an incorrect assumption. While initially limited to laptop computers and other mobile devices, technology that changes the frequency of the CPU is in use in many high-end desktop PCs; disabling its function to maintain a consistent frequency is generally not acceptable to users.

http://msdn.microsoft.com/en-u...y/bb173458(VS.85).aspx

AMD's description for the DCO says, in part...
The AMD Dual-Core Optimizer can help improve some PC gaming video performance by compensating for those applications that bypass the Windows API for timing by directly using the RDTSC (Read Time Stamp Counter) instruction.

and

The AMD Dual-Core Optimizer helps to correct the resulting video performance effects or other incorrect timing effects that these applications may experience on dual-core processor systems, by periodically adjusting the core time-stamp-counters, so that they are synchronized.

So...
TSC = Time-Stamp Counter
RDTSC = Read Time-Stamp Counter

The TSC is a 64-bit register present on all x86 processors since the Pentium. It stores the number of "ticks" since reset, and is incremented every clock cycle. Essentially, sequential reads of the TSC and a little math will give you a single-cycle resolution timer.
http://en.wikipedia.org/wiki/Time_Stamp_Counter

There are a couple of important bits here, 1. Each processor has it's own time-stamp counter, and 2. In a multi-core CPU those individual TSCs are not guaranteed to be synchronized. As a particular application bounces around in execution from core to core, the value of the individual TSCs will vary quite a bit. If the application isn't using that information, that's no big deal. If the application is using the TSC to develop it's own internal timing, having a "floating" TSC value can cause problems. These days (supposedly) well-behaved games use the appropriate API routines instead of the RDTSC instruction.

According to AMD's description of the DCO, it periodically "manually" synchronizes the TSCs of the various cores, so that a RDTSC instruction returns the same value regardless of the particular core handling the app at the moment.

So, though I couldn't find much info on the nvidia option, it looks like the DCO is handling the TSC synchronization between cores, while the nvidia driver is assisting with the multi-threading.

By the way pluto2, I do use Cool'n'Quiet; it keeps my CPU at a nice 28-30°C (vs 38°C w/CnQ off) while surfing and running less demanding apps.

-------------------------
939Dual-SATA2 v1.05, BIOS v2.31
Opteron 165 (CCBWE 0550UPMW) @2.7GHz, 1.35V
TWINX2048-3200C2PT 2.5-3-3-6 1T
Thermaltake Big Typhoon
ATI X1800GTO


Edited: 11/10/2008 at 11:17 AM by fizzbang
 11/10/2008 10:04 AM
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ngwayne
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hi,

fizzbang, thks for your thread, now I have a better understanding of RDTSC n TSC

as for the cool and quiet option, if you guys remember what cool and quiet does, it max the rpm of your cpu fan at high cpu usage to achieve "cool" term n lower down the rpm of your cpu fan when you are not at high cpu usage for your processor to achieve "quiet" term...

so in short disabling cool and quiet lets the cpu fan to stays at max rpm
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