For a current generation midrange offering, there is nothing in the presentation of the HD4850 to suggest otherwise. It shares a lot of similarities with the earlier brethren, the HD3850, with regards to PCB layout and thermals.

ATi allows multi-GPU configuration on the HD4850 too. We'd explore this option in this article after you're done reading my blabber.

The real differences, of course, lies under the hood. Here, you see the RV770 silicon sitting on its throne of solder balls flanked by Qimonda's 1.0ns 256bit memory.

The cards from the 3 titans in AMD graphic boards, namely, Asus, Sapphire & Powercolor!

Our beloved Powercolor sent us a pair of these cards, making the quad Xfire tests possible!

Asus sent us their 680Mhz core TOP edition card.

Last but not least, simplistic design by Sapphire.

Sporting a single PCIe power socket, the HD4850 isn't the most hungry pixel pusher for your PC. Is it a lean card then? RV770's transistor count would give a definitive "no" for an answer.

Keeping all the voltage regulators cool is a pin fin array heatsink that sits above the MOSFETs powering the GPU. Solid Polymer capacitors are used for low voltage decoupling, where their long life and low ESR handles the current requirements of the new chipset. For less critical applications, Sanyo capacitors are seen doing filter duties. These have a very good track record of reliability on par with those of Rubycon or Panasonic.

The HD4850 uses exclusively uPI Semiconductor's power regulation ICs. First up is a the 4 phase GPU Voltage Regulation Module controlled by the uPI6102.

Single phase memory power is provided with the aid of the uPI6101. More about manipulating these ICs in our future modification guide.

The HD4850 is an engineering challenge to cool, with a couple million transistors squashed into an area slightly larger than a dime. Luckily for ATi, the HD3850 was an exercise-in-preparation; pretty much most of the cooling features are ported over.

The single slot thermal solution vents heat towards the rear of the case with the help of a PWM controlled axial cross blower. Flipping over the unit we see that the fan is a 4.8W model.

Active components, with the exception of the GPU, are interfaced via thermal pads. The RV770 die gets a smearin' of grey-goop instead.

Mounting pressure on the GPU is provided by a springy steel frame loaded with springs. Disassembly? Easy! Just a dozen screws needs to be removed. 8 of them are M2.5 and the remaining 4 holding the GPU are M2.

For overclockers on a budget who do not mind noise, and want that extra bit in cooling performance, a little elbow grease is all it takes to force the fan to spin at full speed. Remove the fan connector and locate the blue wire. This is the PWM control wire. Using a pair of tweezers, lift the plastic lip holding the contact, and pull out the wire. Once electrically disconnected, the fan will spin at maximal speed.

With fan control in place, it is indeed hot enough in 3D to warrant this sticker. Fan noise? You know it's there, but it's not glaringly obvious.

With four HD4850s at out disposal, it wasn't all too difficult to fulfill the geekish wet dream of a 4 Way GPU system. Out came the ATi RD790+SB600 Asus M3A32-MVP DELUXE with an AMD Phenom X4 9850. As things got more spidery we took the tarantula-n Enermax Galaxy 1kW to power things up. Memory came from OCZ with Seagate 7200.7s providing necessary storage.

Push some buttons, and Voila!

Clock recognition was problematic on GPU-Z with the HD4850. That wasn't stopping us so we went on to give Jane Nash a little workout.

Initially, things weren't looking so rosy. With 4GPUs, intermittent application errors and artifacts in 2D/3D turned up. Below you can see some of these on-screen quirks.

4xHD4850 delivered 12k in GPU Score despite predicted CPU bottlenecking. Attempting to shift the bottleneck, we tried the Extreme setting on 3DMark Vantage. After a minute's makeup session behind the red blinds, Jane Nash did not turn up in her full (voluptuous?) glamor and instead we were greeted by an error message.

Catalyst 8.6 did not seem to share the same enthusiasm we had for 4GPU ATi power. Since that was so, we had to move on with another test: the all so popular Crysis.

There didn't seemed much to a test we'd run all so often before, until we got down and dirty to actually playing with the spankin' new hardware.

Notice the polygonal to the left of the error window? Not nice at all! Even with a single HD4850, we are unable to benchmark at High settings. This ugly bug seems to have been overlooked in a couple of sites that have tested the HD4850. Simply put, Crysis results you will see in this article will be run at 2560x1600 on Medium settings.

Dropping one HD4850 for a 3GPU system, it was time to watch how things scaled back for the RV770. We'd peep exclusively at DX10 results this time around.

Catalyst 8.6 seemed to have issues load-balancing beyond two GPUs and hence our attempts at running the Extreme preset was futile. Crysis crashed seconds into the timedemo, which leaves us with little choice but to skip to 2GPU testing.

2GPU configuration was where things got better. The driver team appears to have done a good deal better here. Random 2D artifacting went away and Crysis ran fine at Medium settings.

Single GPU tests on the next page.

Single GPU configurations are the most common amongst enthusiasts and naturally the most fuss-free to set up.

Crysis performed better with a single GPU than two. Looks like some work has to be done in ATi's labs.

With 2.5GHz of Phenom power, adding subsequent HD4850s brings about marginal improvements in speed. Scaling from multi-GPU is nonlinear, so we show you the performance change as we add in more GPUs.

CPU scaling is presented below.

With no available tool at the time of writing, we engaged Overdrive. 700MHz was no issue across all four of our RV770s. With the Phenom running at 3GHz (15x200MHz), we got 12.6k 3DMarks in Vantage Performance defaults.

With the ATi HD4850 displaying so many quirks in our tests, many of you must be expecting the product to be slammed down the depths of Hell and banished to the Zone's bin. Many of you may too wonder, why VR-Zone's testing seem to be choppy seas to the Little Red Raft when a great other review sites have their HD4850s successfully complete the plethora of tests. The reason is simple: we test the HD4850 in a variety of situations that you, as an hardware enthusiast, is likely to put the hardware through. Best part of the story? ATi will continue to support the HD4850 with new drivers along the way to iron out bugs and stabilize the product.

Many of you may remember, back in the AGP days, how every Catalyst revision meant a performance boost. It happened with the X800s, and later PCIe graphics accelerators. Things got better in the past, and the same should, (and I trust), would happen today.

For USD199, expect some fantastic performance out-of-the-box, taking up a single slot, and better compatibility in the days ahead. Not too bad a bargain if you asked me. At the end of the day, for the single card budget gamer out there, this might just be the card for you, forget about that 9800GTX+!