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[varsens]

Hi all,

I've recently decided I want to be able to run that 8x8 fort with multiple artificial streams flowing down the mountain and I'm wondering if I have any options outside of buying a new mobo. Most tech support fora seem to go all crazy when you insist that yes, my gaming bottleneck is actually my cpu, thank you very much. I'm hoping the crowd here will have more of a handle on what I'm trying to accomplish, and I know there are quite a few capable hardware guys about. All kudos to Toady, if only more game designers saw cpu, rather than gpu, as the interesting article then perhaps we might have better games, but I digress.

The computer is an a6000n pavilion. The ram, graphics card and power supply have all been upgraded but I've never touched the mobo or the processor. The motherboard is the asus M2N68-LA and the processor is the 64 x2 4200. I've read that it can support the phenom 9600 or the x2 5600, but I'm worried that if what I want to run is DF then upgrading to quad core won't do me much good and I dunno how much of an improvement a 5600 would be.

Are those really what my upgrade options are? Would they make a difference with DF? Am I stupid thinking I can increase the speed by a significant amount without getting rid of the old motherboard?

[Shiv]

Assuming DF utilizes multiple cores (which I don't know if it does, doubt it though since only one of mine seems to light up when I play), get quad core. 

If it doesn't (see above reasoning), then dual core will work, at which point it's all about speed of the cores instead of the number.

[Leperous]

I don't think it supports multiple cores, so the only potential benefit is that other background tasks won't slow down your game.

One thing I'd like to learn is if quad+ core systems have individually weaker CPUs than comparable dual cores.

[varsens]

I'm almost positive that it uses only a single core. I've never seen DF use anymore than 50% of my cpu as reported by task manager, but perhaps that is an inaccurate source. What the wiki says, and what I've seen from playing around with affinity/priority settings seem to confirm that. And it strikes to the heart of my question, I have no need for quad core. I don't run alot of programs at once, I just want to be able to run DF really well. I assume that means quad core is out. Someone please correct me if I'm wrong, otherwise, given that I'm right about what my mobo can handle, does the 5600 constitute much of an improvement over a 4200? I only just got used to the numbering scheme with the old nvidia cards(then they changed to a new one, of course) but that jump means nothing to me other than a set of numbers.

This was all so much easier to understand when a 1ghz cpu meant just that...

edit: /agree with leperous. Thats definitely something I'd like to know. It stands to reason that dual core or even single core would give you more computing power per core per dollar but it seems possible that with engineering constraints or just the manufacturing process(scale?) that it might not be true. Anyone?

[Areyar]

DF is single threaded (and will remain so for the forseeable future according to Toady), so won't run on more than a single CPU.
Get the most powerful CPU you can, a double core if possible, all extra cores will just heat up the CPU for no DF gain.

Good hunting!

[Thief^]

Quad cores do generally have weaker individual cores than a dual core does, for power consumption / heat reasons.

Looking up that motherboard reveals that is an AM2 socket and it only supports up to 90W cpus. HP say it only supports up to the X2 5600+ (I have one of these, it's a good chip), but there is also an X2 6000+ which fits the power limit (and one which doesn't, so be careful if you choose to go for the 6000+).

The Phenom 9600 you mention is a 95W cpu, so is technically outside the power limit of the motherboard. It also only has 2.3 GHz cores, vs the 2.8 GHz of the 5600+ or 3.0 GHz of the 6000+, so would be worse for any application which doesn't support three cores, let alone DF's limit of one.

The 4200+ is a 2.2GHz cpu, so the 5600 or 6000 wouldn't be an earth-shattering upgrade, but it would be 30-40% faster.

[varsens]

Excellent, Thief. Exactly what I wanted to know. Much appreciated.

[Silencer]

Excellent, Thief. Exactly what I wanted to know. Much appreciated.

Also, have you tried the various tricks and tips for performance gains?
A few guides here and there sent me to a playable (capped) 50FPS in most games I've played so far. <_<
I haven't gotten to anything groundbreaking, like population cap of 200, but I'd like to still think it'd run fine then. >_>

[Fredson]

Aparrently Dwarf Fortress IS multithreaded. The game itself uses one core, yes. But the OpenGL release uses another seperate core for the graphics. The new 0.31.0# Versions after the merge will also support 2 cores. So you may look for an old Phenom x3 for AM2+ if they are available.

[Thief^]

Why would you look for a three-core cpu for running a two-thread program?
Especially as the motherboard doesn't officially support AM2+ cpus (AM2 motherboards need a bios update to support AM2+, and I don't see any mention of one being available on HP's site).
EDIT: It's worth keeping in mind that the M2N68-LA the OP has and the M2N68 listed on Asus's site are not the same board. The former is an OEM board made only for HP PCs. The latter is a retail product. The real specifications of the former motherboard are only available on HP's site. It's a pity, as the retail version both supports AM2+ cpus and has a 140W power limit, allowing quad-core cpus to be used.

[Fredson]

Why would you look for a three-core cpu for running a two-thread program?

One for the OS and possibly other programs while two are completely free for DF. Made the experience myself that there IS a performace boost from a dual- to quadcore.

But youre right on the point of AM2+ support. Shit OEM hardware... Probably a 6000+ would be best then.

[Vicomt]

to be honest, the way most modern OS's work is by shuffling the thread around anyway, so vanilla DF will contain itself to a single thread, which your OS will move from core to core as they get overworked (which DF does). This adds a (slight) overhead and speed loss when you use multiple cores, unless you set DF's affinity to a single core using some piece of software

That and multi-core processors are generally slightly lower in grunt (per core) than older single cores used to be, leads to the inescapable conclusion, clock speed is everything, and we've gone back a decade in time.

[Thief^]

Actually, modern dual-cores have all the grunt of old single cores for single-threaded applications, and the modern quads can run as either one high-speed core, or four significantly slower cores, switching on the fly as needed.

In addition, modern cpus do more work per clock cycle than their older cousins, so one core of even a 2GHz modern chip can outperform a once-top-of-the-range 3.8 GHz Pentium 4.

You also vastly overstate the gain of setting affinity. If it mattered that much, the OS would be automatically scheduling cpu-hungry apps onto their own core. Switching from one core to another requires: saving all registers to the (shared) cpu cache, restoring them to the other core. It's a 1000 cycle operation max, out of the 2,000,000,000 cycles (i.e. 2GHz) your chip might have. Even if it happens 1000 times a second (which is extremely unlikely), oh dear, you lose 0.05% of your cpu speed to this travesty!
As I said in another thread, MS only added the ability to force cpu affinity to allow you to fix applications which misuse threads (and so crash on an actual multi-core/cpu system), or which require obscure affinity (e.g. often in a multi-cpu system, one cpu handles hardware interrupts, so you might get a significant gain by forcing a hardware-communication application to that cpu).

[motorbitch]

the question on what cpu type performs best indeed is verry interesting.
for example, i wuld like to know if df scales with caches a lot. i wuld guess it does, but in fact its perfect possible its pure clockcycles.

we wuld need a sticky banchmark thread, where people can post results mesured with some spezific save files and a common mesurement methode.
anyways, more than 2 cores wont help anything, and affinity / priority tweaks wont help at all but rather decrase performance within sub-noticable ranges. (exept for setting priority on realtime, with will hurt a lot.)

so as a fore sure one can say: get highest possible clockspeeds, try to get large caches and dont care about cores.

[Thief^]

I don't know how DF behaves with cache, but considering the data size of a DF embark, a large cache can't hurt.

You can only really be sure you have enough cache when the entire of DF's memory usage fits in cache.