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Question about dual core processors

Started by March 04, 2007 12:22 AM
36 comments, last by Gaiiden 17 years, 7 months ago
Quote: Original post by I_Smell_Tuna
Basically you have the combined power of both processors, so if you have a 2Ghz dual core processor you basically have a 4Ghz processor. However the game needs to be multi-threaded in order to utilize both cores if it's not you'll only have the power of one core. Keep in mind that there is some overhead when using multiple cores so you'll never get 100% utilization of both processors.



Usually there are problems due to comminications overhead and task mismatching that leads to the second CPU executing at much less than the 100% (when used for the same App). Hopefully the gaming companies will be learning to maximize that (wont be too long before the QUADs are common). Smarter AI sucks up incredible amounts of CPU capacity and we will be needing all that the processors can produce.

--------------------------------------------[size="1"]Ratings are Opinion, not Fact
Quote: Original post by agi_shi
Adding liquid nitrogen to any processor won't help in performance. See, as long as it runs at a reasonable temp, then performance won't really differ. Only time it WILL differ is when you're running at above normal temps. and the CPU is throttling down to not melt.


There you go again. Do you understand the concept of overclocking? Do you understand the need for increased cooling while overclocking? Do you understand how much more you could overclock a processor if it's being cooled by something ridiculous like liquid nitrogen? If you don't understand any of the previous questions then please excuse yourself from this thread as you obviously have no idea what you're talking about.

Quote: Besides, I don't really think we need benchmarks. I'm 120% sure practically any 8000MHz processor will be faster than most stock C2Ds.


Of course you need benchmarks! If for nothing else to show that the computer doesn't crash after running for 5 minutes! Massive overclocking tends to make things unstable and the fact that they didn't show any tests would seem to indicate that they couldn't keep the computer running long enough to run any.

Quote: Original post by Ezbez
Quote: Original post by Ravuya
Most games now are single-threaded anyway, so you will see zip improvement from adding an extra CPU.


Really? I've never used a dual core computer extensively (and certainly not benchmarked it), but that's not the impression I had gotten from articles. My computer is doing a lot of other tasks while I'm playing a game (386 threads right now). Surely having that task load partially on another processor could benefit a game's performance, even just marginally?


This is true to some extent but background processes usually aren't enough to hinder game performance on a single cpu, unless you're running something stupid like Norton. The new dual-core cpus run games faster because the architecture is better, not necessarily because it has two cores. What you could do with a dual-core though is encode mp3s or something while playing F.E.A.R without a noticeable performance difference.
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Actually, you're the one being obtuse here. Here is what you said:
Quote:
You're comparing apples to oranges here. If you applied the same cooling system to an E6300 the the E6300 would be able to outperform the P4EE.

How the f*ck does that imply any sort of overclocking whatsoever?

Quote: Original post by tstrimp
Quote: Original post by agi_shi
Adding liquid nitrogen to any processor won't help in performance. See, as long as it runs at a reasonable temp, then performance won't really differ. Only time it WILL differ is when you're running at above normal temps. and the CPU is throttling down to not melt.


There you go again. Do you understand the concept of overclocking? Do you understand the need for increased cooling while overclocking? Do you understand how much more you could overclock a processor if it's being cooled by something ridiculous like liquid nitrogen? If you don't understand any of the previous questions then please excuse yourself from this thread as you obviously have no idea what you're talking about.

Yeah, I do. I see you do, too. What you DON'T understand, though, is the fact that I'm only quoting EXACTLY what you said.

In fact, this machine I'm running right now I built and overclocked myself. X2 3800+ (lowest of the line) is running at X2 5600+ speed (2.8GHz vs. 2.0GHz). Stable as hell, never busts 53C.
Quote:
Quote: Besides, I don't really think we need benchmarks. I'm 120% sure practically any 8000MHz processor will be faster than most stock C2Ds.


Of course you need benchmarks! If for nothing else to show that the computer doesn't crash after running for 5 minutes! Massive overclocking tends to make things unstable and the fact that they didn't show any tests would seem to indicate that they couldn't keep the computer running long enough to run any.

Sure, it's probably unstable there. My X2 3800+ was unstable at 2.9GHz. But it's not - if you digged you'd come to the thread with the guy explaining stuff. The reason they didn't do any benchmarks is because they ran out of LN2.
Quote:
Quote: Original post by Ezbez
Quote: Original post by Ravuya
Most games now are single-threaded anyway, so you will see zip improvement from adding an extra CPU.


Really? I've never used a dual core computer extensively (and certainly not benchmarked it), but that's not the impression I had gotten from articles. My computer is doing a lot of other tasks while I'm playing a game (386 threads right now). Surely having that task load partially on another processor could benefit a game's performance, even just marginally?


This is true to some extent but background processes usually aren't enough to hinder game performance on a single cpu, unless you're running something stupid like Norton. The new dual-core cpus run games faster because the architecture is better, not necessarily because it has two cores. What you could do with a dual-core though is encode mp3s or something while playing F.E.A.R without a noticeable performance difference.

Don't forget, some games ARE multi-threaded. Crysis, for example, will dynamically branch threads as much as it feels your processor can handle. Technically I'll be able to run Crysis at all high/max once I get an X1950XT. X1950XT is just about as fast as a 8800GTS, except it's got more ram, faster ram, and is only ~210$ (cheaper than even the 320MB 8800GTS).

Maybe you're the one who needs to excuse yourself? [grin]

j/k
Quote: Original post by agi_shi
Actually, you're the one being obtuse here. Here is what you said:
Quote:
You're comparing apples to oranges here. If you applied the same cooling system to an E6300 the the E6300 would be able to outperform the P4EE.

How the f*ck does that imply any sort of overclocking whatsoever?


Sorry, but no, there is such a thing as 'context'. You were talking about a massively OC'd CPU vs a stock CPU, from this context it can be inferred that tstrimp's comment was directed at OCing a C2D using the same cooling to keep it in context with the discussion.

End of the day, when people make statements such as 'X will out perform Y' they mean with stock cooling OR compartive OCing of the hardware; not massive and ultimately useless (yes, running out of Liq. Nit. is useless) OCs which are done just to see how far you can push a chip.

Quote: Original post by phantom
Quote: Original post by agi_shi
Actually, you're the one being obtuse here. Here is what you said:
Quote:
You're comparing apples to oranges here. If you applied the same cooling system to an E6300 the the E6300 would be able to outperform the P4EE.

How the f*ck does that imply any sort of overclocking whatsoever?


Sorry, but no, there is such a thing as 'context'. You were talking about a massively OC'd CPU vs a stock CPU, from this context it can be inferred that tstrimp's comment was directed at OCing a C2D using the same cooling to keep it in context with the discussion.

End of the day, when people make statements such as 'X will out perform Y' they mean with stock cooling OR compartive OCing of the hardware; not massive and ultimately useless (yes, running out of Liq. Nit. is useless) OCs which are done just to see how far you can push a chip.


No, see, "out-perform" does NOT mean "out-overclock". "out-perform in overclocking", yes - but just "out-perform" in no way suggests overclocking.
Quote: Original post by agi_shi
No, see, "out-perform" does NOT mean "out-overclock". "out-perform in overclocking", yes - but just "out-perform" in no way suggests overclocking.


I'm not sure I understand what you mean.


I take CPU-A that runs better than CPU-B on the same stock cooling with no overclocking.


I put a super cool cooling system on CPU-A and CPU-B and massivly overclock them.


CPU-B now kicks CPU-A's ass because CPU-B is overclocked, but CPU-A remains running at stock levels?

right,...



Intel's new line of processors run so much cooler than P4s, and it was my understanding that their heat output doesn't increase as much as you overclock it compared to the hotplate of a processor the P4 is.
Incase you didn't notice what this suggests to me, is that you can put the same cooling system on a CD2 as on a P4, but overclock the CD2 even more.

But I could be wrong.
Old Username: Talroth
If your signature on a web forum takes up more space than your average post, then you are doing things wrong.
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Quote: Original post by agi_shi
No, see, "out-perform" does NOT mean "out-overclock". "out-perform in overclocking", yes - but just "out-perform" in no way suggests overclocking.


Within the context of the post he was replying to and the discussion, yes it does, it can be inferred from surounding information and doesn't take a great leap to see that that is what he was talking about.
Quote: Original post by Talroth
Intel's new line of processors run so much cooler than P4s, and it was my understanding that their heat output doesn't increase as much as you overclock it compared to the hotplate of a processor the P4 is.
Incase you didn't notice what this suggests to me, is that you can put the same cooling system on a CD2 as on a P4, but overclock the CD2 even more.

But I could be wrong.


That's true. You can overclock the E6400 by more then 30% while still running stable without anything more then the stock heatsink/fan.

Quote: Intel Core 2 Duo E6300 & E6400: Tremendous Value Through Overclocking
What we didn't know previously however was how far we could overclock retail E6300/E6400 CPUs, and furthermore we had no idea what a highly overclocked 2MB Core 2 Duo CPU would perform like. Armed with two B1 stepping Core 2 Duo CPUs, one E6300 and one E6400, we went to task on overclocking them. Our goal wasn't to reach the absolute highest overclocks using high end cooling, but rather the maximum stable overclocks easily attainable with a stock Intel heatsink/fan. Undoubtedly we could have reached higher frequencies with more elaborate cooling, but we were more interested in the bare minimum of what was attainable - and we weren't disappointed.

Our E6300 was able to reach 2.592GHz using a 370MHz FSB at 1.400V (up from 1.320V stock):

Our E6400 was a bit more successful, reaching 2.88GHz using a 360MHz FSB at 1.350V (up from 1.300V stock):


Taking a look at the benchmarks you can see that the OC'd E6400 runs nearly as fast as the Core 2 Duo Extreme X6800 (2.93GHz/4MB) for 1/4th the price.
And back to the OP question.

A multicore CPU will run a single-threaded app at the same speed as a SINGLE one of its cores (or slower), never faster, no matter what.

A multicore CPU will run a multi-threaded app some arbitrary amount faster than a single one of its cores, in general if it wasn't written very poorly. That amount faster can actually exceed the amount you get from multiplying number of cores * speed of one core in very specific situations where there are certain types of resource contention between the threads, but in almost any normal situations it is some amount more than the speed of 1 core, and less than the theoretical multiple of that core.

At a previous company under BeOS, our mutli-threaded application ran 98% faster on dual processors than on singles processors ... AND had more responsive behavior (less latency from user input to feedback) than a single double-speed CPU. In fact, due to OS design in BeOS, our program when fully bogged down was more responsive on dual Pentium 233 (MMX or PII can't rember) than it was on a single Pentium III 733. But when the user interface / responsiveness wasn't taken into account, it computed just a little less on dual 233s than on a single 550, and just a little more on dual 550s than on single 866 (very little because our app only really needed a certain amount of performance to max out).

Under Linux when we ported it, the application ran about 70% faster on dual cores than on a single, and even less on Windows 98 (although we only ever ported the core logic used in the server, not the GUI). Windows NT 4.0 (and 2000) ran dual core processors much better than Windows 9x (like 10-15% more relative performance).

I have not done similar benchmarks on any current OSes or Processors because my work these days is primarily business web applications, but I can say the web server and db servers run between 60% and 90+% faster on dual processors (or cores) than on single cores.
Quote: Original post by Talroth
Quote: Original post by agi_shi
No, see, "out-perform" does NOT mean "out-overclock". "out-perform in overclocking", yes - but just "out-perform" in no way suggests overclocking.


I'm not sure I understand what you mean.


I take CPU-A that runs better than CPU-B on the same stock cooling with no overclocking.


I put a super cool cooling system on CPU-A and CPU-B and massivly overclock them.


CPU-B now kicks CPU-A's ass because CPU-B is overclocked, but CPU-A remains running at stock levels?

right,...

Huh?

What do YOU mean?
Quote:
Intel's new line of processors run so much cooler than P4s, and it was my understanding that their heat output doesn't increase as much as you overclock it compared to the hotplate of a processor the P4 is.
Incase you didn't notice what this suggests to me, is that you can put the same cooling system on a CD2 as on a P4, but overclock the CD2 even more.

But I could be wrong.

Yeah, it runs at lower temps. But the P4 is the overclocking king, I'd say. The fastest C2E I've seen was at 5.5GHz - that's what, a 2.5GHz increase? The fastet P4 was 8GHz - a 5GHz increase *cough* double that of the C2 *cough*

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