View Full Version : 64 bit gaming? on Doom3???

11-28-02, 06:14 PM
Not sure if this should be here or in the processor forum, but I am wondering if Doom3 will support 64 bit cpu's. I know a 64bit version of Unreal exists, so I would imagine eventually most huge games would come in dual versions (when the cpu's are out), but does anyone know anything about plans for Doom3?

11-28-02, 07:07 PM
Whats the difference between the two? how much better is 64 bit?

11-28-02, 09:54 PM
I'm sure they'll do it, I see no reason for them NOT to...if not on 1st release, maybe cuz it's not a priority, I'm sure they'll be a patch then...

12-26-02, 02:07 AM
in case anyone still cares about this. i really hate digging up old dead threads, but the question was never sufficiently answered. while looking for old quotes from Carmack i ran across this.


How will the next generation of 64bit CPUs affect Doom 3
64 bit is not going to speed up Doom 3. In fact there may actually be a minor slowdown since the pointer references are all in 32 bit, which will mean a hit to memory bandwidth which is the real gating problem.

12-26-02, 02:42 AM
Well it would be faster if it was desigen on 64bit processor , becouse when Intel few years ago showed how Itanium pure 64bit CPU can run same program redesigned to take full advantage of 64bit code , it ran some 20 times faster then on 32bit code & Todays P4/Athlon

But us Carmack pointed out Doom3 was designed for 32bit code they would have to fully redesign the game :o

12-26-02, 05:27 AM
hmm, the way i understood it was if it was 64bit "optimized" then all pointers would be 64bit instead of 32bit, which would bottleneck memory bandwidth more.

even if the game was designed for 64bit, if that is the issue at hand, how would you get past it?

12-27-02, 10:17 AM
it ran some 20 times faster then on 32bit code & Todays P4/Athlon


There is noway on earth comparing a clock for clock 64bit cpu V 32bit cpu, with equal software (i.e. not using SUPER DUPER 64bit SIMD on one, and not on the other) will run 20 times faster on the 64bit cpu.

Not including any special SIMD type instructions, and that the same instructions take the same number of cycles on each cpu, the code would take the same amount of time. Possibly even slower, as the 64bit code would use more memory, and miss more cache lines because of it.

You _can_ make better use of the 64bits and provide extra performance. But only if you code specificially for the 64bit architecture.

Like soo much of the BS marketing they prolly compared a program using 64bit SIMD to an generic 8086 coded version on the P4/athlon.

Any other speed increase is architectural improvements, not because of the increase in bit processing.

12-29-02, 09:39 AM
Carmack said he wouldn't bother doing a port.

One can make some of the stuff 64 bit, and some 32 bit, for not sacrificing performance. On that same note, I'm hoping Clawhammers will be updated to 512k cache because I'm hearing 256 isn't really enough for 64 bit stuff.

Guess I didn't have much to say...|leaves the building|

12-29-02, 11:51 AM
64 bit cpus is only useful for 2 things.

1) 64bit SIMD stuff. A few areas in game could use this.

2) Servers with loads of ram. Gets around the memory limitation of 32bit addresses.

Apart from that theres not much point to 64bit cpus.

12-29-02, 07:05 PM
I think it could be useful for AI...which may be indirectly what you just said, I couldn't say. But...
I like the new architecture an awful lot.

By its second core revision (much like Thunderbird) it should rock

12-29-02, 08:14 PM
Yeah the extra registers is nice. About time too.. Most RISC cpu's have about 32 registers. Compared to x86 derived 8 registers.. hahaha 8!! *smirk* ;)

Although it does mean AMD are gonna have to get their own compilers out, or convince M$ to stick clawhammer code options in their dev studio. Otherwise we're not gonna get use out of the registers at all.

12-29-02, 08:24 PM
I think they (MS) 're workin on it.
I used to follow AMD rumors and stuff, but lately I really don't care at all. Rumors make me sick after all this 'GFFX WILL HAVE GODS HAND EMBEDDED ON THE 3RD CHIP FROM THE LEFT' type crap.

12-29-02, 09:08 PM
Originally posted by Nutty
Yeah the extra registers is nice. About time too.. Most RISC cpu's have about 32 registers. Compared to x86 derived 8 registers.. hahaha 8!! *smirk* ;)

yes, 8 registers is annoying. always have to swap things around 'n stuff :mad: