In direct competition with the new Radeon HD 3400 cards, Nvidia’s GeForce 8400 GS and 8500 GT are media-centre-focused. Neither will have you gaming at an acceptable level with recent games, but they share similar new technologies.

As with ATi’s Hybrid graphics, these low-end cards support Nvidia’s GeForce Boost, which can increase 3D performance when paired with the latest Nvidia integrated GPU. Motherboards are still on the way, so we don’t know how effective it will prove, but we don’t see many people choosing these for gaming, although it’s nice to have the option.

Unlike ATi’s PowerPlay, however, you can’t switch to integrated graphics to save power. You can pair two 8500 GTs in a standard SLI configuration, but the 8400 GS doesn’t support this.

With a 450MHz core clock and just 16 stream processors, neither promises to offer much gaming ability without sacrificing resolution and quality.

The 8500 GT managed a just-about-playable 29fps in Crysis at 1024 x 768 with the uninspiring Low settings, and 28fps in Call of Duty 4 at 1280 x 1024 and Medium settings – results that are not too bad considering the price. But the 8400 GS performed almost identically to the HD 3450 in our tests: not very well.

Video is a different matter. If you’re using Vista, both 8400 and 8500 cards can take on the full workload of decoding 1080p Blu-ray video, potentially allowing PC users to appreciate effects such as picture-in-picture. Silent models are common, and you should be able to find both half- and full-width cards to suit the size of your chassis.

Which of the low-end cards you ultimately choose depends on what it is exactly that you want. The 8400 GS is dirt cheap at $40; the 8500 GT costs $60 but may just about have you playing older games, while the HD 3450 costs the same but offers ATi’s PowerPlay technology – and we think it’s this that will deliver the greatest benefit for most people.