AMD Radeon HD 6790 Graphics Card Review - HotHardware

AMD Radeon HD 6790 Graphics Card Review

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When AMD and NVIDIA release a new batch of next-generation graphics processors, gaps typically form in their respective product stacks as the entire top-to-bottom line-up of new products is fleshed out over time. When new GPUs are introduced, they usually offer increased performance at a given price point, which drives the cost of comparable previous-generation products downward. Occasionally the supply and demand of both the new and old products will result in a larger than desired price disparity between the new parts and the older ones that still remain on the market. It’s those large price disparities that are where product gaps show.

Such is the case with AMD’s current product stack. At the top of the line-up, AMD has the Radeon HD 6900 and 6800 series parts, but the lower-end of the market is still covered by Radeon HD 5000 series parts. Disregarding the few remaining Radeon HD 5800 series parts that will eventually sell out, the $100 to $120-ish Radeon HD 5770 is currently the first step down from the $150 to $180-ish Radeon HD 6850. AMD aims to fill that relatively large price gap between those two models with the new card we’ll be showing you here today, the Radeon HD 6790.

This first official member of the Radeon HD 6700 series isn’t completely new (we say official because the Radeon HD 6770, which is a re-branded 5770 is available to OEMs). In fact, it is based on the very same "Barts" GPU powering the Radeon HD 6800 series. A few functional blocks within the GPU have been disabled, however, ultimately resulting in a lower performing, but decidedly more affordable, DirectX-11 class GPU. We’ve got the full specifications, details and pics below.  We'll then take a look at performance on the pages ahead.

AMD Radeon HD 6790
Specifications & Features
Process
Transistors
Engine Clock
Stream Processors
Compute Performance
Texture Units
Texture Fillrate
ROPs
Pixel Fillrate
Z/Stencil
Memory Type
Memory Clock
Memory Bus Width
Memory Data Rate
Memory Bandwidth
Load Board Power
Idle Board Power
40nm
1.7B
Up to 840 MHz
800
Up to 1.34 TFLOPs
40
33.6 GTexel/s
16
13.4 GPixel/s
53.8 GSample/s
GDDR5
Up to 1050 MHz
256-bit
Up to 4.2 Gbps
Up to 134.4 GB/s
150W
19W

We’re not going to harp on the physical attributes of the Radeon HD 6790 we tested for a couple of reasons. First off, according to AMD, the card you see pictured here will never see the light of day. It is a reference model based on the same design as the Radeon HD 6850. Secondly, all of AMD’s board partners are readying custom Radeon HD 6790s that will look nothing like the reference card and may even sport only a single power connector.

  

  
A Radeon HD 6790 Reference Card

The reference Radeon HD 6790 you see pictured here is built around the 40nm ‘Barts’ GPU, which is comprised of roughly 1.7B transistors. As it is configured on the Radeon HD 6790, the GPU will sport 800 stream processors, with 40 texture units, and 16 ROPs (Radeon HD 6850 cards have 960 stream processors, 48 texture units, and 32 ROPs). The 6790 does, however, have the same 256-bit interface to its GDDR5 RAM. This reference card has an 840MHz GPU paired to 1GB of 1050MHz memory (4.2 Gbps data rate), for a peak textured fillrate of 33.6GTexels/ s and 134.4GB/s of memory bandwidth. Idle board power is rated at 19W with a load power of 150W.

Outputs on the Radeon HD 6790 consist of dual DVIs (one dual-link, one single-link), dual mini-DP outs, and an HDMI port. Board partners may choose to different output configurations with their custom designs, however.

  
HIS Radeon HD 6850 iceQ Turbo

Before we move on to the Radeon HD 6790 performance evaluation, we want to point out that custom, factory overclocked Radeon HD 6850 cards, like the HIS Radeon HD 6850 iceQ Turbo, have recently hit the scene at price points not much higher than the 6790. Competing parts from NVIDIA, namely the GeForce GTX 550 Ti, were also available in factory overclocked editions from the get so. As such, we’ve included numbers from some of these factory overclocked cards, alongside the reference clocked models, to paint a more complete picture of performance at all price points ranging from about $149 to $179.

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Nice review!

I have to say, it looks like a nice card for the mid-range crowd but the disappointing performance numbers kind of turn me away from this card.

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Eh, performance really isnt bad considering the price and its competion. The issue for me is these 3rd Tier cards (4830, 5830, 6790) always have odd thermals, odd price points, and dont really seem to have a place in the market except to fill a relatively small void. Plus the 6850 is only a few bucks more and performs noticeably better so honestly i dont see a need for this card...its sorta awkward....

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I agree with both of you. Definitely not a card for a power user and it is awkward.

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Very true, but this card is not top rung in fact is is 3 or 4 down from the top rung in ATI's products so the perf is gonna be a bit off.

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There 850/870 are ATI's money makers I would think. So there performance compared is better than the comp. The 970 is more for BA right's!

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I my opinion, I think its time that more games get added to the test( Crysis 2,Call Of Duty, Battlefield 2) and second , these are low budget cards...while its right that they get tested in 1920x1200 and 2650x1600, this review should have the results for resolutions of 1024x768, 1280x1024 and 1680x1050, which is what they were meant for.

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@Sammy - 1024 and 1280 and compeltely pointless to test with current-generation mid or high-end graphics cards. Everything will run at playable framerates and / or be CPU bound. AMD actually targeted 1920 with this card, so I tested that resolution and one more taxing to show how it holds up in more stressful circumstances. What's interesting to note is that the 6790 actually wins more tests at 2560 than the 550 Ti, which bodes well for it in the future. Had that res not been tested, we wound't know that. 1680 is a useful resolution, but we're talking 1.76MP (1680) vs. 2.07MP (1920). The performance different is not going to be nearly as dramatic as the delta from 1920 to 2560.

As for the games, I like to stick with a set group of games / apps for as long as possible so readers can go back to previous articles and get an idea for performance not only over time, but versus older cards that may not get re-tested once they're EOL.

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Marco C:


 What's interesting to note is that the 6790 actually wins more tests at 2560 than the 550 Ti, which bodes well for it in the future. Had that res not been tested, we wouldn't know that. 1680 is a useful resolution, but we're talking 1.76MP (1680) vs. 2.07MP (1920). The performance different is not going to be nearly as dramatic as the delta from 1920 to 2560.

As for the games, I like to stick with a set group of games / apps for as long as possible so readers can go back to previous articles and get an idea for performance not only over time, but versus older cards that may not get re-tested once they're EOL.



 what is most interesting to me is the way the cards are consistently evaluated around here by Marco using a 'suite' of tests to evaluate where the card performance sits. Without that it would be pretty hard to see exactly where the card performance is and do the comparison.

Even though I have a HD 5770 it would be interesting to checkout similar benches and tests to learn along the way and have a much better appreciation for the efforts in the reviews.

Too bad my screen resolution is inappropriate as mentioned but all the same going to work with I currently have

because it would be fun.Smile

Thanks Marco

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Every time u see Marco on steam hes testing out something new! :D

Nice review, its a decent card in its range.

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Inspector:
its a decent card in its range

agreed,...not everyone can spring for a top of the line card for their system and it's good to know what works well in the lower priced categories too. I install discreet graphics for people with built-in video systems all of the time. I do it to free up their system from the video robbing the RAM and to speed up graphic performance for them.

One card that I like is the 1GB-MSI N440GT for about $79.00. It gives a tremendous boost to a low end systems graphics capabilities, and it is a Fermi card that's 3D capable, and has CUDA, and PhysX too. The card comes with regular and also low profile configurations for slim cases. (Dell boxes)

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