by Ilya Gavrichenkov
11/22/2004 | 11:01 PM
Even if you are not playing Half-Life 2 yet, you will hardly be able to avoid this game. This 3D shooter, which has every right to be nominated for the title of the Best game of the Year 2004 proved really exciting and attractive for the commencing gamers as well as for the hardcore ones. This effect is certainly achieved due to unbelievable environment created by the game developers, as well as the thrilling plot and outstanding effects.
One of the indisputable strengths of the world created in Half-Life 2 is definitely very strong artificial intelligence of all enemies and friends, and very realistic physics of the environment and characters, which very often makes you nearly believe that things are happening for real. To tell the truth, the physical model of half-Life 2 game is worth a separate detailed discussion. This game is based on the today’s most advanced Havok engine, which makes all the objects in the game obey the laws of physics. Despite the size and the importance of the given object for the story and the scene – no matter if this is a large truck or a small stone at the sea shore – all of them do obey fundamental laws of physics and are affected by forces of gravity, friction and flotation.
This way it is not only the powerful graphics card responsible for flawless display of the environment and characters on the screen that determines the number of fps you can get in Half-Life 2. When playing half-Life 2, the system CPU is also loaded to the full extent, as it is actively involved into the physical calculations and those dealing with the characters’ artificial intelligence models. That is why we decided to undertake an extensive testing of 29 contemporary platforms based on different processors, following our detailed investigation of the actual graphics cards performance (for details about the performance of graphics cards in the new half-Life 2 please see our article called Half-Life 2 Performance Preview: The Graphics Hardware Squeezer).
The developer of Half-Life 2 game, valve Software recommends using a CPU supporting at least 2.4GHz actual clock frequency (over 2400+ performance rating). However, according to our experience, this game has already proven to be very CPU-dependent, so any additional MHz above the recommended 2400 will definitely work for the best. We have already seen proof to this point during our graphics cards tests in Half-Life 2: in certain scenes the systems performance remained at the acceptable level even in the hardest work modes. All this indicates very clearly that the system performance in Half-Life 2 in many cases depends on the CPU.
All in all, there is nothing surprising about Half-Life 2 being so dependent on the CPU speed. Since the game developers decided to pay special attention to the physical picture of the world and the artificial intelligence of the characters created in this game, it appeared simply impossible to do it without loading the CPU pretty heavily. As a result, Half-Life 2 game turns out to be a really efficient and illustrative processor benchmark, being very similar to real-time physical modeling tasks with simultaneous visualization of the calculation results.
We tested the processors in Half-Life 2 game by playing the preliminarily recorded demo scenes. Luckily, Half-Life 2 uses its own physical engine even for pre-recorded demo playback, so the fps rates obtained throughout this test does reflect the fps rate during actual gameplay. For our testing needs we used the same five demos we have already introduced to you in our article devoted to the graphics cards performance in Half-Life 2. Note that we decided to use all these demos, because as we have just seen Half-Life 2 loads different system components differently in each demo. Therefore, we assume that the CPU performance can also vary in different demos.
We also discovered that the use of high resolutions, FSAA and anisotropic filtering in Half-Life 2 doesn’t make the fps rate less dependent on the processor speed. In other words, even when the work mode is very heavy and resource consuming for the graphics subsystem, Half-Life 2 remains very CPU dependent. That is why we decided to perform our tests in two video modes. In the first case we tried to unload the graphics subsystem as much as possible: we set 1024x768 resolution, disabled anti-aliasing and anisotropic filtering. In the second case we used the same settings a gamer would use for a powerful graphics accelerator: we set the 1280x1024 resolution, enabled 4x anti-aliasing and 16x anisotropic filtering. Other settings remained the same in both cases and were at their maximum all the time, so that we could ensure maximum image quality: model detail – high, texture detail- high, water detail – reflect all, shadow detail – high, shader detail – high.
Of course, we used the most powerful graphics card for our processor benchmarks: ATI RADEON X800 XT working at 500MHz chip and 1000MHz memory frequency.
The complete list of tested processors as well as other testbed components are given below:
The tests were run in MS Windows XP SP2 operation system with the DirectX 9.0c installed.
The typical feature of all scenes with the word “canals” is the presence of large water surfaces. Water surface is one of the toughest tests for a graphics card in Half-Life 2. Nevertheless, it in no way means that the CPU is doing nothing in this case.
As we see, the fps rate does depend a lot on the CPU in the “light” graphics card mode. The performance difference between the top CPUs and the mainstream CPUs is over 50%. In general, we can state that Athlon 64 processors from AMD proved to be the fastest here. In fact, the performance of the top Intel Pentium 4 models is as high as that of AMD Athlon 64 3200+.
However, this result was obtained in slightly artificial conditions. Let’s see what the situation is going to look like when we switch to a heavier graphics test mode.
With enabled FSAA and anisotropic filtering the CPU performance doesn’t really affect the results. It is probably the graphics card that appears the bottleneck in this case. However, this is not at all surprising: Half-Life 2 uses a special shader for water surfaces, which loads the graphics processor really heavily.
Nevertheless, I have to note that the advantage of Athlon 64 processors, which we have already pointed out to you in the previous case didn’t prove to be true here. LGA775 systems using Pentium 4 processors run almost neck and neck with their AMD rivals. Again, this is all pretty logical: PCI Express graphics card used in the LGA775 platform worked faster than a similar AGP 8x solution. So, the graphics bus bandwidth seems to be also having some influence on the Half-Life 2 performance. Unfortunately, there are no mass platforms yet for AMD Athlon 64 processor, which would use PCI Express x16 bus, therefore, we dare state mostly theoretically that it makes much more sense to have a graphics card supporting PCI Express x16 bus if you are going to play Half-Life 2 in graphics-heavy modes. Anyway, the performance gain provided by this bus is not that dramatically big and makes only 2-3%.
In this demo we can see a short fight against zombies, which are defeated with the help of a gravity gun loaded with anything available at hand. This weapon should really load the CPU. Moreover, we also witness a few huge explosions, which blast effect scatters all objects and characters around.
The situation is very similar to what we have already seen in the previous demo. AMD processors are again far ahead their rivals from Intel due to bigger computational potential.
When we run the tests in “heavier” resolution, LGA775 platform manages to significantly improve its performance due to PCI Express x16 bus. Pentium 4 processors tested in Socket 478 platform, which uses AGP 8x bus cannot boast the same success. For instance, Pentium 4 Northwood working at 3.4GHz clock frequency is totally defeated by AMD Athlon 64 3200+, while Pentium 4 on the Prescott core working at the same core frequency even falls behind Athlon 64 3000+. So I wouldn’t be so enthusiastic about the Pentium 4 platform performance in Half-Life 2: the victory here is not absolutely fair I should say.
Is there anything better than a nice car-ride along the steep riverside? This is exactly what we are going to do in the next demo. However, our hero will not just drive through the d2_coast_05 demo scene, but will also have to shoot a few enemies and overcome a few obstacles lying in his way.
If you have read our article devoted to the graphics cards performance in Half-Life 2, which was put up a few days ago, you should remember that this is a very processor-dependent game level. Even in the top resolution the CPU appeared a system bottleneck preventing the performance from going all the way to the maximum. But before we take a look at the top resolutions, let’s check out the systems performance in 1024x768 with disabled FSAA and anisotropic filtering.
Well, this is a pretty familiar picture, actually, with that only difference that AMD Athlon 64 processors are even farther ahead of their competitors. Well, it looks like this is typical of Half-Life 2: the more processor dependent the level is, the better perform CPUs with K8 architecture. And here the difference is simply dramatic: Athlon 64 2800+ outperforms Pentium 4 3.6GHz! Moreover, the pretty old Athlon XP CPUs seem to have caught their second wind: even Athlon XP 3200+ appears faster than any of the Pentium 4 3.2GHz.
Now let’s see how the picture will change when we set “normal” resolution.
Wow, this is a truly impressive CPU-dependence. We set the resolution to 1280x1024, enabled FSAA 4x and 16x anisotropic filtering, and the results remained almost the same. I have every right to state that the Half-Life 2 performance in this scene is fully dependent on the system CPU. This is exactly why you might want to have a faster processor for this game.
Here we are participating in a town battle. Our hero fights side by side with a strong robo-dog, which grabs the passing car and throws it into the enemies following all physical laws. Another excellent example of one more CPU-dependent situation.
Again we see the same picture. Despite a drastic change of the gaming environment AMD CPUs retain their indisputable leadership.
In fact, it would be incorrect to say that the CPU is the only performance limiting factor here. When we set the resolution to a higher one the fps rate does drop noticeably. However, the CPU does play an important role here anyway and again we see AMD’s triumph. It looks like it was not for nothing that Valve developers called K8 architecture the most suitable for their new game. Also note that Hyper-Threading technology, as well as SSE3 instructions haven’t been implemented in Half-Life 2 at all.
Well, Valve software engineers didn’t actually strive for making use of all most advanced features offered by contemporary Intel CPUs.
The last demo used for our today’s test session also appeared very dependent on the CPU performance. In d3_c17_12 level we see a common street fight with a lot of soldiers involved on both sides. And as we have already seen, when it comes to shooting, CPU power can never be too much.
I believe that no comment is necessary here. By this time you should have already understood that AMD processors show their best in Half-Life 2 much more successfully than the solutions from Intel.
The situation hardly changes when we set heavier resolution for the graphics subsystem. Here we see that even in the heaviest work modes the CPU does determine the overall performance of the system.
Half-Life 2 appeared exactly the game where the CPU performance and potential do matter a lot. Even in high screen resolutions with enabled FSAA and anisotropic filtering, a powerful graphics card is not enough to ensure high fps rate. Quality physical model of the gaming environment in Half-Life 2 does require a powerful CPU.
Since physical modeling sets most of the workload on the central processor during Half-Life 2 gameplay, AMD’s solutions appear the fastest as they have always been known for their high performance in scientific math1ematical and physical tasks. These processors appear a way ahead Intel CPUs: Intel’s top processors lose even to the mainstream AMD solutions. This is also partially explained by the fact that Valve doesn’t use any of the Intel’s advanced features, such as SSE3 or Hyper-Threading, which should significantly speed up Intel Pentium 4 based platforms.
In conclusion we decided to make a graph illustrating average performance of the testing participants in Half-Life 2 basing on the results obtained in the above discussed five demo scenes and two resolution modes:
Well, this diagram can actually serve as a direct advisor when choosing a CPU for Half-Life 2. If you got really excited about the new game and would like to upgrade your system in order to enjoy comfortable gaming experience in Half-Life 2, this diagram should help you to make the right choice. And please keep in mind that we also have a very detailed guide, which will help you also decided on the graphics card for your system (for details please see our recent article called Half-Life 2 Performance Preview: The Graphics Hardware Squeezer).