Unreal Engine 3 creator Tim Sweeney talks 64bit/PPUs/DX10/Dual Cores

[Sanborn]

Awesome interview, and I had no idea that 64-bit won't see much improvement unless you have 4GB or more of system memory. Can someone explain the reason in a response ?

Anything in Blue is my response
Anything in Red is me highlighting something I find interesting


http://www.firingsquad.com/news/news...searchid=11906

Even though video and PC game developers debate about "visuals vs gameplay" when making their titles, there's no doubt that having games look their best is a big factor in any game's success. FiringSquad will be running occasional interviews with game graphics programmers to get their views on how they use the best of the latest PC hardware along with some predictions for things to come. We are honored to have for our first interview on this subject to be Tim Sweeney, the co-founder of Epic Games and the main programmer for their Unreal game engines, including Unreal Engine 3 which will be first used for their own title Gears of War:


FiringSquad: First, Intel and AMD are pushing dual core processors and in the next year four core processors are due to be released. How will Epic support this kind of tech in Unreal Engine 3 and will there be any need for special programming to fully support multi core CPUs in PCs?

Tim Sweeney: The work we did in optimizing for Xbox 360 and PlayStation 3 enables Unreal Engine 3 to scale well to multi-core PC CPUs. The latest dual-core CPUs from AMD (Athlon 64 x2) and Intel (Core Duo 2) provide excellent performance for Unreal Engine 3, and the engine will further scale up well to the 4-core CPUs coming later.

FiringSquad: The 64-bit CPU has taken longer to really appear than some people expected. Do you think 64-bit CPUs will become more popular and how will Epic support it in their Unreal engine?

Tim Sweeney: Yes! We first showed the Unreal Engine running on 64-bit at AMD's Athlon 64 launch several years ago. Since 64-bit Windows XP wasn't widely adopted, that delayed the industry-wide move to 64-bit. But it's clear that Windows Vista will mark the transition point where all buyers of new PCs have a stable 64-bit OS "out of the box", finally making the technology mainstream. We'll certainly be supporting it, though the more immediate benefit comes on the tools side -- to game developers and mod teams authoring content -- where your development machine has 2-4X the memory as your expected user configurations. Keep in mind that 64-bit only brings significant benefit when your PC has 4GB or more memory.

I fully believe that Epic will be the first company to utilize quad core. Might be 2008+ when it happens but it will still be neat to see.

FiringSquad: Game physics are getting more and more attention as well with more attention being put into destrucible objects and better collisions. Epic supports the AGEIA hardware processor currently with Unreal Engine 3. What sorts of special features will be used in Uneal Engine 3 while using the AGEIA processor.

Tim Sweeney: Ageia's solution provides a fully-general, hardware-accelerated physics solver, so it's more a question of magnitude than of features -- it enables more than a factor of 10 increase in the number and complexity of interacting physics objects including ragdolls, particles, and so on. With Unreal Engine 3, game developers who target the physics hardware will be able to use that additional performance to add whatever kind of detail they want.

$250 for more particles that bounce

FiringSquad: What about using a graphics processor or one of the multi-CPU cores for hardware physics support? Will Epic also support that kind of feature or do you think AGEIA's way is best?

Tim Sweeney: Ageia's PhysX includes a software physics solution that already scales very well to multi-core CPUs -- both on PC and on console platforms, so physics will be one of the primary beneficiaries of the additional CPU power in 2- and 4-core CPUs.

GPU-accelerated physics is another interesting avenue to explore. NVidia and Havok showed some cool GPU-accelerated physics demos at GDC, but the precision and feature set was fairly limited, fine for things like particles and rubble but falling short of being a general solution. The Direct3D/OpenGL-based GPU programming model is too restrictive to enable the sort of fully general physics solver we're interested in for vehicles, ragdolls, etc, but very interesting things could happen here as GPUs and their software interfaces grow to expose more general computing power.

The thing to pay attention to for ^^ is the fact that YES - GPU's will be like extended general processors with the coming age of DX10 developments. AGEIA will get blown away by physics offloading onto GPU and dual core+ processors without a doubt.
FiringSquad: HDR lighting is also getting a lot of attention in more PC games. Will the Unreal Engine 3 have that kind of support and how will that help the graphics in games that use it?

Tim Sweeney: Yes, HDR is a huge factor in the look and feel of next-generation games. Unreal Engine 3 uses it pervasively to enable a wider range of scene brightnesses than was possible in the past.

Thank god

FiringSquad: More and more games are using extensive pixel and vertex shading for visual and art effects. How does the Unreal Engine 3 support these feature currently and how will pixel and vertex shaders be used in the future, particularly with Windows Vista and DirectX10 support?

Tim Sweeney: Previous engines approached shaders as a programmer-oriented feature: a programmer writes some shader code, and then later an artist supplies some textures for it. In Unreal Engine 3, all shader creation takes place in UnrealEd's visual shader creation tool, and is 100% artist-driven, putting complete control over the visual style and appearance of a game in artists' hands. DirectX10 adds more features and performance, rather than fundamentally changing anything.

I've read many other interviews and it really sounds like Epic has streamlined the creativity in its development. Hopefully it will make UT2007 actually "unreal"

FiringSquad: Finally, Mark Rein has said that Intel is hurting the PC gaming industry through its use of intergrated graphics in PCs. Is this a real threat and if so what can be done about this from the game developer's side?

Tim Sweeney: The basic premise of integrated graphics is that you can reduce the cost of a new PC by putting a cost-effective GPU on the motherboard, rather than requiring a separate add-in card. This is a sound idea.

The problem with Intel Integrated Graphics is that Intel isn't delivering sufficient performance and features to run DirectX9-focused games decently. Though PC game developers are accustomed to scaling features and performance by a factor of 2-3 to support the range of low- to high-end PCs available, Intel Integrated Graphics is off par by a factor of 5-10 and is thus practically unsupportable.

As a result, the vast majority of next-gen games, which are being designed around DirectX9 and targetted at both PC and next-gen consoles, won't be able to run decently on the majority of low-end PCs which contain Intel Integrated Graphics. Thus a large swath of PC owners are being segregated out of the next-gen PC gaming market, leaving only the high-end PC gamers, and that's not clearly a large enough audience to support PC gaming as an industry.

Ultimately, this just moves the gaming audience away from PCs, to consoles. Watching this unfold feels tragic, because Intel has been very successful in supplying the whole market -- including even the lowest-priced segments -- with excellent, high-performance CPUs. But, without decent DirectX9 graphics capabilities, these PCs will never be adequate for gaming.

Yeah except when Bearlake comes out with DX10 support they will have nothing to complain about

[Celcius]

Very interesting article.
It'll be really interesting to see UT2007 on Kentsfield + DX10 in 64-bit mode!

[oshua]

To your question about 64bit computing with 4GB is that with 32bits the OS can only address 3.XXGB of RAM. With a 64bit system the OS can address 2^64 bits of RAM.

[JamesAvery22]

Awesome interview, and I had no idea that 64-bit won't see much improvement unless you have 4GB or more of system memory. Can someone explain the reason in a response ?

if the architecture stays the same the difference between a 64bit CPU and a 32bit CPU is the 64bit CPU can do operations on 64bit numbers... So for a 4bit and an 8bit CPU the 4bit can do operations on any number between 0000 and 1111. The 8bit can do 00000000 and 11111111.
With 32bit the number of addresses in memory are limited to 4,294,967,296(the max 32bit number). So if you have more than 4GB a 32bit system can't address anything else because it can't handle the operations.

Being a 64bit CPU doesn't increase performance. adding 0001 and 0010 on a 4bit CPU is just as fast, if not faster as adding 00000001 and 00000010 on a 8bit CPU.

[Sanborn]

Thanks James, that makes sense. But does that mean that you won't see a 64-bit performance increase unless you have 4GB or you probably won't see a 64-bit performance increase until the programs utilize that much ram?

I only ask because TS:
"Keep in mind that 64-bit only brings significant benefit when your PC has 4GB or more memory. "

[oshua]

You wouldn't see a benifit till programs use 4GB+ of RAM.

[Revv23]

good article, 4gb+ might be sooner then we think, imo.

[drwowe]

To your question about 64bit computing with 4GB is that with 32bits the OS can only address 3.XXGB of RAM. With a 64bit system the OS can address 2^64 bits of RAM.

That isn't quite true, 32 bit mode can access more than 4 gig using a technique called PAE. It basically involves mapping different parts of the RAM into the 32 bit space at different times, kind of like how DOS extenders used to work.

But it is simpler in 64 bit mode, all of the 32 bit shuffling adds overhead.

[uOpt]

Keep in mind that 64-bit only brings significant benefit when your PC has 4GB or more memory.

Which is, of course, nonsense.

64 bits is about virtual, not physical memory.

Among other things it gives you a flat address space where you can map above 4 GB even on a 256 MB machine, and it gives you native 64 bit arithmetic, which speeds up quite a few applications these days. And twice as many registeres in the case of x86 to x86_64, which is about four times as many freely usable registers (because the first 8 are too booked up all the time).

[BlackX]

This is really worth waiting

[J-Mag]

The thing to pay attention to for ^^ is the fact that YES - GPU's will be like extended general processors with the coming age of DX10 developments. AGEIA will get blown away by physics offloading onto GPU and dual core+ processors without a doubt.

Blown away? There is nothing to blow away. I think we are still in the infancy phase of Physics tech and any speculation on future events has no basis in fact.

Yeah except when Bearlake comes out with DX10 support they will have nothing to complain about

Just because DX10 is supported doesn't mean it will be playable with DX10 games. Intel does not want to incur massive costs on IGP chipsets as they sell these to OEMs. I think you are a far to optimistic.

[DilTech]

UE3.0 won't be the first to take advantage of quad core, CryEngine 2 will.

Crysis is being optimized for the 4x4 platform, crytek already made that statement.

Yeah except when Bearlake comes out with DX10 support they will have nothing to complain about

Intel IGP, able to handle gaming in dx10? Not going to happen, Intel's top-IGP right now barely handle UT2k3 at 640x480! Using intel's igp to play UT2k7 or Crysis will be like using a FX5200 to play Far Cry. Support and performance are 2 COMPLETELY different things.

[onewingedangel]

I'm sure intel will have to pull something out on their integrated graphics over the next year as their now competing wth ati directly, and a rx200 chipset and turionx2 would hammer a merom and 965g in even simple games even though merom is a good deal more powerful. Whether they do this by integrating dedicated memory, or increasing the number of graphics pipelines - somethings going to have to change - thanks to the fact that vista may perform better on amd systems than intels, all due to the graphics subsystems.

[Hicks]

I wonder how much the CPU will effect Crysis and Ut2007, even when there dual core and quad core optimized.

Surely the lastest gen GPU, is better than having the best CPU, at 1600x1200, with 4XAA i can't see it bein that much different, to the limiations we have now?

[Sanborn]

^^ physics use the second core in Crysis

[grimREEFER]

crysis is optimized for 4 cores, so it might be the first game to take advantage of quad cores
also, i guess ageia has the best solution for physics, all the other ones are bad according to Tim

[brandinb]

doesnt really matter how many cores new game engines utilize because they will all be gfx limited.

[nn_step]

Nice read

[grimREEFER]

doesnt really matter how many cores new game engines utilize because they will all be gfx limited.

well, at least a pentium d 805 and an fx57 will be on the same playing field now lol

[MaxxxRacer]

Yeah except when Bearlake comes out with DX10 support they will have nothing to complain about

Just because DX10 is supported doesn't mean it will be playable with DX10 games. Intel does not want to incur massive costs on IGP chipsets as they sell these to OEMs. I think you are a far to optimistic.

Precisely. Just look at ATI and NVIDIA's low end cards when dx9 came out. none of them could play dx9 games well, and NVIDIAS (the FX5200) offering was laughable at best when it came to dx9.

Intel will be no different for Bearlake.