CPUs and GPUs Confusion

[watercooled]

Something I keep saying, be VERY careful with CPU gaming benchmarks, they're often run at very low settings and resolution to take the bottleneck off the GPU and often meaning hundreds of FPS; this is not representative of most real-world scenarios. This is often mentioned by the authour, including Anandtech just not on the 'bench' page.

I agree with others saying go with 6300 over 6100, and further details about your intended uses would help with recommendations.

[Pob255]

From the benchmarks and reviews I've seen so far I'd say the new fx6300 edges out the i3 3220, but only on a couple of titles.

As to all you people saying that in the future we'll see more games using more cores, well that's been said since the core2quad and we're only really just starting to see it and even then the number of games is still small.

I would say go with the FX6300 over the i3, not because of any future games but if he's planning on going sli, because adding in extra gpu's (sli/crossfire/or dual gpu card) adds a chunk to cpu demand and the extra load will get shunted over to a spare core.

One final note about cpu game bench mark numbers, many sites still use fraps or similar to record the footage to calculate the fps results and that's something that will add a big chunk to the cpu load and again it will get shunted onto a core and you are going to notice the effect on a dual core cpu if something is seriously hammering one core as most games are now make use of two cores.

[Willzzz]

adding in extra gpu's (sli/crossfire/or dual gpu card) adds a chunk to cpu demand and the extra load will get shunted over to a spare core.

But that's not how it works. You can't just shunt extra load onto a spare core, you can't just divide up load into equal size pieces.

Like in real life, some jobs can be easily divided up, many hands make light work. Other jobs you just can't do that, you can't speed up an operation by having 6 surgeons working on one patient.

[watercooled]

Newer games tend to be fairly well threaded though - no, you can't just split the CPU load into infinite chunks but it's often possible to extract a good level of parallelism from games, and considering the current consoles are showing their age in terms of single-threaded performance, developers are already doing it.

[DanceswithUnix]

As to all you people saying that in the future we'll see more games using more cores, well that's been said since the core2quad and we're only really just starting to see it and even then the number of games is still small.

I would say that it has been said since the original single core Athlon FX and Pentium 4 days. Getting dual core was often considered a waste of money. Slower in benchmarks for all the major games. When was that, 2005?

These days it is normal for games to use two or three cores, the direction of progress is clear, but so is the slow rate of improvement.

[scaryjim]

But that's not how it works. You can't just shunt extra load onto a spare core ...

That depends on where the load comes from. I would imagine that in Crossfire/SLI the driver takes most of the management overhead, rather than the game engine, and the driver will have its own threads. The OS will schedule those threads, and if there are more cores than busy threads then it will schedule on idle cores rather than time-sharing on busy cores. So in that specific case - i.e. managing the overhead from multi-GPU setups - the overhead from the driver almost certainly will be handled better by CPUs that can handle more concurrent threads.

Of course, that also applies to anything running in the background that will use CPU time. Forgot to kill a background process before gaming? 6 threads will handle that better than 4...

[Willzzz]

Yeah that's true. Is the driver overhead high for CF/SLI?
I pretty sure the vast majority of extra CPU load is going to come from the game due to the increased frame rates.

I was running a background process yesterday pegging 3 of my 4 threads for 100%, thought the game seemed a bit choppy! 6 threads is certainly good for forgetful people

[scaryjim]

Yeah that's true. Is the driver overhead high for CF/SLI?

I don't know if it's high, but there definitely is some. The driver has to handle assigning rendering tasks across 2 GPUs, and data has to funnel across both the special bridges and the PCIe lanes. All of that is managed by the drivers, so there has to be some load attributable to that. It'd be interesting to run a crossfire/sli setup and monitor CPU usage by the driver compared to running a single card - anyone willing to volunteer?

I doubt the game engine piles much additional load onto the CPU, tbh, although I'm sure the load does vary depending on the graphical power available - but the same thing would happen if you moved to a single more powerful GPU rather than a dual card setup. There's a big difference between being CPU bottlenecked just because you've got a lot of GPU power, and handling the additional overhead of the GPU power being divided between two cards.

[ik9000]

I would do happily but my mobo won't support SLI. (the moral of which is ALWAYS CHECK and don't assume)

[rolfcore]

i play a mix of games. wanting to play things like BF3 on watchdogs when it comes out. That sorta thing.
mainly a gaming PC but ill be using to for my uni work too. Budget is £550 including monitor.

[Pob255]

Yep scaryjim, has it, it's the extra management load which are separate threads which the OS can shunt onto idle/low workload cores, which is why having more core than the game normally utilises will see a bigger improvement on an sli system which is turn makes it look more cpu bound.

I would say that it has been said since the original single core Athlon FX and Pentium 4 days. Getting dual core was often considered a waste of money. Slower in benchmarks for all the major games. When was that, 2005?

These days it is normal for games to use two or three cores, the direction of progress is clear, but so is the slow rate of improvement.

Athlon 64 x2 was the first dual core amd and the pentium D the first intel dual core both in 2005
Both of them where only slower in benchmarks when compared to a faster single core processor, only on games that didn't use multi core processing, there where a couple in 2005 that did eg city of heroes implemented multi core support in 2005 and the difference was noticeable because it was very cpu heavy and could easily max out single core cpu's (mmo's have always been more cpu heavy although at the time CoH was probably the most graphics heavy MMO and the only multi-core supported MMO)

Yes games will continue to increase the number of cores they can use over time, my question is when? as much as we might hate it games are still being held back by the current console generation.
From my understanding of it on the xbox 360 a game can only use two of the 3 cores because the third is reserved for other duties, managing netcode and other OS type duties, this does have an effect on pc games as most are designed with multi-platform release in mind, even if a game is not a straight port they are still often designed from the ground up to make possible porting less difficult.
This is a big reason many games still often don't use more than two cores.

I still say that the amd fx6300 because we are starting to see more games better written to use more than two cores, but it's not going to be an overnight change we'll not see dual cores unable to cope for a while yet.