The HD 4850 is the middle chip from the HD 4800-series of GPUs. It's a range that's impressed us in the past: whereas the HD 4600 parts are too weak to be serious pixel-pushers and the X2 parts are too dear for all but the most hard-core of gamers, the HD 4800s hit a sweet-spot of performance and price.
While the HD 4850 shares plenty of specifications with its dearer cousin, the HD 4870 - 800 stream processors and 956 million transistors - the clock speed is slower at 625MHz and that card's GDDR5 memory is replaced by either 512MB or 1GB of GDDR3.
The hardware may not be quite as beefy as the HD 4870, but the price of around $273 is far more tempting, especially when you consider the performance you're getting for the cash.
The card didn't struggle with Crysis until we ramped quality settings to their highest levels, and both Far Cry 2 and Call of Duty 4 were playable with high settings selected. The HD 4850 struggled only with Call of Juarez's most demanding test - every option at maximum with a resolution of 1920 x 1200.
The HD 4850 is also impressive when stacked against the competition. It's faster than the slightly cheaper 9800 GT and just as quick as Nvidia's 9800 GTX, which costs $110 more - proof that ATI's aggressive approach is working.
Performance such as this - from a so-called mainstream card - underpins ATI's recent resurgence in the graphics market. If the HD 4870 is a tad too expensive then breathe easy; while the HD 4850 isn't quite as quick, it's $200 cheaper and still an excellent performer.