Intel's quad-core rings in a new era of enthusiast systems

Posted by Wolfgang Gruener

Bellevue (WA) - We've heard the story over and over again: Dual-cores are the fastest chips you can buy, period. While that claim may be true in many cases, it is especially not true for gaming: Games have not yet embraced multithreading and are lagging behind. Half-Life 2 developer Valve, however, believes that this scenario will change quickly and promises a 3.4x performance gain with four cores.

The transition to multi-core-gaming: Valve Hardware Day 2006

Click here to see pictures of the Core 2 Extreme QX6700...

Valve has been holding its hardware day briefings for some time now. This year, this event coincided, not quite accidentally, with the day Intel lifted the embargo from publishing benchmark results of the first quad-core processor. We were able to report unofficial results some time ago and, if you follow our stories, you already know that the quad-core chip, previously code-named "Kentsfield," is quite a monster in terms of raw processing power.

However, as dual-core chips before, Kentsfield wasn't quite showing its horsepower in games and when Valve told us that it would be shedding some light on performance gains in multi-core gaming, which so far was almost a contradiction in itself, it was a no-brainer to accept the invitation, fly out to Seattle to get the scoop first hand.

Industry sources these days are unusually cautious about quad-core game performance and typically tell us that benchmark results should be taken with a grain of salt and the understanding that purchasing a quad-core system means buying a capability that will arrive in software sometime in the future, I was skeptical of what I would hear. After a few hours with Valve, I am convinced that - at least for gamers and enthusiasts - dual-core is outdated. Quad-core is the way to go. Here is why.

Valve is the first, but certainly not the last, major game developer to announce an aggressive transition of its game engine to multi-threading capability. The company confirmed that it has been working on a transition for about ten months (read: since the release of the Pentium D 900 series) and is coming close to be releasing multi-threading capability in its games: Valve is targeting a "pre Half-Life 2 Episode 2" release sometime in the first half of 2007. Upgrades of older games are planned as well.

Core 2 Extreme QX6700, code-named "Kentsfield"

According to Valve, quad-core will be resulting in more performance and some new features for the user immediately and a lot more features down the road. The company mentioned that frame rates will improve to a certain degree. But at some point, better frame rates may not be the only satisfying feature anymore and we will begin to see new and substantially upgraded features that cannot be supported by today's single- and dual-core processors. Those features will include especially particle simulation, which comes very close to what gamers perceive as physics simulation today. Valve explained that a substantial part of particle simulation needs to be supported by the CPU: In fact, the game developer said that quad-cores are capable of running physics - without the real need of SLI physics, Crossfire physics or a discrete board that carries Ageia's physics processor.

The company hopes that particle simulation will create more physical interactivity that feeds back into the game experience and allows the gamer to feel a "greater presence" within the game.


Kentsfield offers 8x the particle performance of the Pentium 4

Valve did not provide a lot of details about possible performance gains with quad-cores in physics. However, the firm said that four Kentsfield cores provide roughly 3.4 times the particle performance of one Kentsfield core, which would indicate a nice scaling capability of Valve's improved game engine. The power of a quad-core chip is even more impressive when compared to a Pentium 4 3.2 GHz processor: The game developer said that a quad-core Kentsfield has roughly eight times the particle simulation horsepower of the aging single-core chip.

Benchmark results provided by Valve

Artificial intelligence, short AI, is the other main area targeted by multi-core processors. The company showed off simple "experiments", which demonstrated that a quad-core chip is powerful enough to simulate the behavior of up to 500 independent critters - which were able to go after enemies as a group, which could move while avoiding dangerous objects such as fire pits. The demo critters could also be motivated to arrange in a certain order, which showed that a substantial number of independent objects could be controlled in a very precise way.

Even the simple graphics of those demos provided a clear hint of how powerful quad-core processors will be. Five years ago, game developers complained about smallish processing horsepower that allowed them to simulate the behavior of only one intelligent object per screen. Valve has reached 500 simple critters already and engineers mentioned that it can do the same with about 200 soldiers in another demo. In the end, this could mean that objects will be acting just as realistic as they look today.

Some physics effects run by Valve. The fire pits also served as obstacles that were avoided by demo critters

All these benefits require a completely new way to program games. For Valve, it means that the company has to invest into a transition which engineers called "significant" and Valve founder Gabe Newell, who briefly stopped by for the briefing, "painful." Leaving a time of creating single-threaded code that depends on the chronological events in a series of events behind, the company has found a strategy to utilize quad-cores as much as possible - which means that a game will try to exhaust all four cores at any given time.

The company refers to its development strategy as "hybrid threading," which uses a combination of coarse threading and fine grain threading. Coarse threading is relatively simple to create and will put entire tasks, such as rendering or AI, onto different cores. Coarse threading apparently does not scale very well, resulting in a speed gain of about 1.2x, according to Valve. Fine grain threading, on the other side, will divide tasks across multiple cores and complement coarse threading to approach a 100% utilization of each core. Valve's engineers mentioned that this approach scales extremely well and should result in some "exciting" results. For pure development purposes, the company said that quad-core will save "thousands" of hours in calculation time - but conceded that programming multi-threaded applications will get much more complicated.

Controlling 500 individual intelligent objects: In this case, the demo critters are motivated to move into a specific position

All those benefits appear to specifically address quad-cores - and you may have noticed that I mentioned a little earlier that quad-core is the way to go, not two dual-cores. While it may be a bit pre-mature to judge how well two dual-core Xeons will perform against Kentsfield and how well AMD's 4x4 platform (which will rely on two dual-cores as well) will compete with Kentsfield, Valve provided some indications that a quad-core chip will deliver the benefit the company is intending to provide. Tom Leonhard, one of the lead developers in Valve's multi-core team, said that the performance differences between two dual-cores and one quad-core could be significant in certain scenarios. He stressed that Valve is trying to avoid such scenarios, but could not confirm that this could be achieved across the board.

Pressed to provide a better idea which will be the better performing gaming platform, Valve declined to make any recommendations. Instead, company officials noted that benchmarks results of hardware sites should offer enough detail for enthusiasts to find the best choice. However, Gabe Newell stated that Valve has delayed the purchase of new computers until now - and will replace its development machines with quad-cores (read: not 2P dual-core systems) immediately.

At least for now it is clear that enthusiasts who consider their PC as an investment to a certain degree should not buy a dual-core system anymore. If you are throwing $4000 or more into a serious gaming computer this Christmas, then Intel's Kentsfield (officially called Core 2 Extreme QX6700) may be your only choice. Valve declined to discuss AMD's 4x4, which - in combination with the firm's confirmation that it will transition its development systems to quad-core - leaves a question mark behind the capability of the platform: It is yet another indication that AMD may need a quad-core processor rather sooner than later.

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