RV670: AMD ATI Radeon HD 3870

Rounding things up:

If we take in everything we’ve covered over the past seventeen pages, I think it’s fair to say that the Radeon HD 3870 is a successful refresh of a product that was plagued with so many problems. I don’t think I need to go on about the problems that there were with R600 and the Radeon HD 2900 XT – there’s a new product in town that’s so many times better than the Radeon HD 2900 XT that I can’t begin to describe it.

That’s not to say that RV670 is without its problems, but a lot of the major ones have been worked out. There’s still a complete lack of hardware-based MSAA resolve in RV670’s render back-ends, which hampers performance when you’re using anti-aliasing. However, having spent a lot of time talking with AMD’s GPU product managers, I decided that it wasn’t that the current generation Radeon’s anti-aliasing performance was particularly bad – it just isn’t as good as Nvidia’s efficiency at 4xMSAA.

The reason we say this is because performance on Nvidia’s hardware drops off at 8xMSAA to such an extent that the GeForce 8800 GT is no longer noticeably faster than the Radeon HD 3870 – so much so that you’d be pushed to tell the difference between the two in a blind taste test. It could be that Nvidia just hasn’t tuned its hardware to efficiently use 8xMSAA though, as its 8xCSAA mode is almost as good as 8xMSAA and isn’t quite so severe on the performance stakes.

Regardless, we were pleased to hear that R700 won’t suffer from the same problems and, from what I understand, there will be hardware-based MSAA resolve in there for scenarios when shader-based anti-aliasing is less than optimal for what the developer is trying to achieve. In the past we were spoiled with great anti-aliasing performance and quality on ATI’s hardware, and it just hasn’t been as good as it should be this generation – AMD knows this.

The other thing that still irks me a little is the chip’s architectural efficiency – I can’t help but feel this card should (and would) crucify Nvidia’s GeForce 8800 GT if code was written in such a way to take advantage of the VLIW architecture or if AMD had opted for a more versatile architecture that doesn’t suffer from some of the constraints that we’re used to seeing in GPUs of past years, before the unified shaders came to be.

In my opinion, a unified shader architecture should be a very efficient and elegant solution to the graphics problem, but the VLIW design appears to be a bit of a mistake based on the titles that are available now... not the titles that might be available in the future. It’s almost as if the ATI engineers have tried to be too clever with the architecture, rather than focusing on something that’s a little more brute force - a little like the earlier X1600 memory architecture, which was most efficient for games that would be released long after the card was antiquated. The problem for AMD is that the card’s performance can, at times, be inconsistent and that doesn’t really help its cause.

Anyway, that’s enough talking about the problems I still feel there are with AMD’s current architecture – let’s move onto some more positive things, because RV670 is anything but R600 take two.

A good place to start would be power management, as it’s probably the single most impressive thing about the Radeon HD 3870 because when you’re not gaming, your GPU is sitting there burning coal. AMD has addressed this problem by pulling PowerPlay across from its mobile GPUs and introducing it onto the desktop to deliver a new level of aggressive power management technology to desktop users – the result is a GPU that consumes 16W less power than the competition at idle.

Not only is idle power great though, the card also dynamically changes its clockspeeds depending on GPU load. If you’re playing a game that’s inherently CPU limited, the Radeon HD 3870 will not be running at full whack. And when the card’s running at full load, it consumes the same amount of power as Nvidia’s GeForce 8800 GT.

On a related note, AMD has designed a heatsink/fan combination that’s quiet. Not only does it not spin up when you’re idling, it also doesn’t spin up during heavy gaming sessions either – it’s about time we had this from a Radeon. AMD has absolutely hit the nail right on the head with the Radeon HD 3870’s stock cooler.

Performance isn’t bad either, but it’s never really a true contender for the GeForce 8800 GT’s crown in the mid-range. But, the point is that the Radeon HD 3870 is currently much cheaper than the GeForce 8800 GT, so if you’re willing to sacrifice a little bit of performance and save yourself some money, you could find that the Radeon HD 3870 is a great buy for your needs.

While we’re on the subject of performance, we should really talk about DirectX 10.1. At the moment, I don’t think it’s a massive selling point; instead, I think it’s more of a checkbox feature and even AMD has admitted to bit-tech that DirectX 10.1 is never likely to become a minimum requirement for PC games. That should help to quash the suggestion that DirectX 10.1 would make all current hardware obsolete, because it couldn’t be farther from the truth.

That’s not to say that DirectX 10.1 is useless though – far from it, in fact. There are some great additions into DirectX 10.1 that will make game developers' lives easier in the long run and it’s paving the way for the future of PC gaming. For example, it’s about time we had proper MSAA support in games that use deferred rendering techniques, because I can’t help but feel that every attempt to add anti-aliasing into an engine which uses deferred rendering has failed thus far. It’s 2007, almost 2008 in fact, and anti-aliasing should be a given these days – and even Microsoft believes that all hardware should support a minimum of 4xMSAA.

The question I was dying to get an answer to was whether the Radeon HD 3870 (or HD 3850 for that matter) would be fast enough to use the new features included in DirectX 10.1 when actual games that use the features start to ship. We’re talking about games that are at least ten months away here, so given that the hardware isn’t the fastest on the market today, it’s going to look decidedly mid-range by the time those games ship. As a result, I wouldn’t get too hung up on DirectX 10.1 features and instead focus on your current gaming requirements.

Final Thoughts...

AMD’s ATI Radeon HD 3870 is a great product for the money, but its price point is incredibly important to its long term success. I say this because unfortunately for AMD, there’s a certain G92-based graphics card from Nvidia which delivers, in some cases, quite a bit more performance for not much more financial outlay. With that said though, if you’re an AMD/ATI fan or are on a budget, the Radeon HD 3870 is by no means a dud – this and the Radeon HD 2900 XT are like night and day.

It's a great time to be in the market for a new graphics card, because there are treats on both sides of the fence. If it wasn’t for the GeForce 8800 GT, the Radeon HD 3870 would be one of the few graphics card worth serious consideration if you want value for money and, as a result of this, it earns a solid recommendation from us.

• Features
• x
• x
• x
• x
• x
• x
• x
• x
• x
• x
• 10/10

• Performance
• x
• x
• x
• x
• x
• x
• x
• x
• -
• -
• 8/10

• Value
• x
• x
• x
• x
• x
• x
• x
• x
• x
• -
• 9/10

• Overall
• x
• x
• x
• x
• x
• x
• x
• x
• x
• -
• 9/10

What do these scores mean?