ATI Radeon HD 4770 review
本帖最后由 ~DeatHMooN~ 于 19-5-2009 04:37 编辑Meet the Radeon HD 4770
So then, to understand what is powering up that Radeon
HD 4770 first we need to learn what's inside it. The basis of the card is in essence the graphics processor and it's video memory, slapped onto a PCB with crystals, PLLs, voltage regulators, resistors, capacitors etc etc.
The GPU used on this card has the following codename -- RV740.
RV740 is the replacement of the RV730 (Radeon HD 4650/4670), that product line will still remain in the market for a while, yet we think RV740 in time will replace it completely as this series is just too strong. Why you ask? Well, the RV740 is really a disciple of RV770, yes indeed... the Radeon HD 4850/4870.
By making this move, AMD slash ATI will redefine the budget to middle class product line-up as performance of the strongest RV740 based product will move upwards in-between the HD 4830 and horribly close to HD 4850 performance.
It is a very spiffy card when it comes to performance (for the money of course). Radeon HD 4770 has 640 shaders (stream processors). The final core frequency for the card we tested is 750 MHz.
RV740 is based off a 40nm production node and is equipped with 128-bit memory. Now before your go "aaahw, we lost half the framebuffer bandwidth due to 128-bit memory", here's the thing. The RV740 is equipped with GDDR5 memory. This GDDR5 memory is running at 800 MHz, that boils down to 3200 MHz, 3.2 Gbps effective, and that's just over 50 GB/sec of bandwidth on the final memory configuration.
Now if you cut down the memory bus in half to 128-bit you lose half the bandwidth, ATI compensates for that by doubling it up again with GDDR5 memory. It's a bit of a tradeoff here and there. See, 128-bit memory is fairly cheap to use and does return a heap of framebuffer bandwidth thanks to the higher frequency memory. Also I can imagine a simpler design in the PCB such as using less wires and thus a cheaper design. On the flip side, gDDR5 does have somewhat slower memory latency timings. But granted, this choice makes a lot of sense, as the benchmark results will show.
Now I've fired off some math at the most generic denominators and when we place things in a chart, you'll gain some perspective of product differences.
ATI Radeon
HD 4850ATI Radeon
HD 4830ATI Radeon
HD 4770ATI Radeon
HD 4670ATI Radeon
HD 3870# of transistors956 million956 million826 million514 million666 millionStream Processing Units800640640320320Clock speed625 MHz575 MHz750750 MHz775+ MHzMemory Clock2000 MHz GDDR3 (effective)1800 MHz GDDR3 (effective)3200 MHz
GDDR5
(effective)2.0 GHz GDDR3 (effective)2.25 GHz GDDR3 (effective)Math processing rate (Multiply Add)1000 GigaFLOPS740 GigaFLOPS960
GigaFLOPS480 GigaFLOPS497+ GigaFLOPSTexture Units4032323216Render back-ends16161688Memory512MB GDDR3512MB GDDR3512MB GDDR5512MB GDDR3512MB GDDR3/4Memory interface256-bit256-bit128-bit128-bit256-bitFabrication process55nm55nm40nm55nm55nmPower Consumption (peak)~110W~110W~80W~59W~105WGeek facts: the RV740 houses640 stream processors, 32 texture memory units (TMUs) and 16 renderoutput units (abbreviated as ROPs). As stated, It features a 128-bitwide bus using GDDR5 memory, bumping up bandwidth that rivals equallyclocked GDDR3 with double the bus width producing 51.2 GB/s of memorybandwidth, and for a product like shown today... bandwidth iseverything.
But let's seat the card into out test PC and check out what it means in power consumption, heat and noise levels.
http://www.guru3d.com/imageview.php?image=17572 The thermal envelopeIt's always interesting tomonitor new developments, and for AMD a large problem to tackle waspower consumption. They brought it down severely in 2D (desktop mode).As a results we see very IDLE temperatures at roughly 55 Degrees C (131F), a little on the high side.
Once we start stressing the GPUthe temp goes up big-time, we level at roughly 71 Degrees C (160F). Andthat's just a great temperature really.
http://www.guru3d.com/imageview.php?image=17561
Observe Rivatuner monitor GPU temperature while stressing the GPU.
Noise Levels coming from the graphics card / coolingWhen graphics cards produce alot of heat, that heat usually needs to be transported away from thehot core as fast as possible. Often you'll see massive active fansolutions that can indeed get rid of the heat, yet all the fans thesedays make the PC a noisy son of a gun. I'm doing a little try-out todaywith noise monitoring, so basically the test we do is extremelysubjective. We bought a certified dBA meter and will start measuringhow many dBA originate from the PC. Why is this subjective, you ask?Well, there is always noise in the background, from the streets, fromthe HD, PSU fan etc etc, so this is by a mile or two not a precisemeasurement. You could only achieve objective measurement in a soundtest chamber.
The human hearing system hasdifferent sensitivities at different frequencies. This means that theperception of noise is not at all equal at every frequency. Noise withsignificant measured levels (in dB) at high or low frequencies will notbe as annoying as it would be when its energy is concentrated in themiddle frequencies. In other words, the measured noise levels in dBwill not reflect the actual human perception of the loudness of thenoise. That's why we measure the dBA level. A specific circuit is addedto the sound level meter to correct its reading in regard to thisconcept. This reading is the noise level in dBA. The letter A is addedto indicate the correction that was made in the measurement.Frequencies below 1kHz and above 6kHz are attenuated, where asfrequencies between 1kHz and 6kHz are amplified by the A weighting.
TYPICAL SOUND LEVELS Jet takeoff (200 feet)120 dBA Construction Site110 dBAIntolerable Shout (5 feet)100 dBA Heavy truck (50 feet)90 dBAVery noisy Urban street80 dBA Automobile interior 70 dBANoisy Normal conversation (3 feet)60 dBA Office, classroom50 dBAModerateLiving room40 dBA Bedroom at night30 dBAQuiet Broadcast studio20 dBA Rustling leaves10 dBABarely audible We start up a benchmark andleave it running for a while. The fan rotational speed remainsconstant. We take the dBA meter, move away 75 CM and then aim thedevice at the active fan on the graphics card.
The cooler design itself is anoisy little f*xker, however... ATI keeps fan rotation below 40%... andas such the cooler is silent. We measured 39 dBA from the system. Oncethe graphics card is getting hot by fully utilizing it, we get stuck ata 40~41 dBA measurement which you can hear, softly.
Very nice, but if you decide to manually control the fan for more airflow, above 60% RPM it will be noisy.
本帖最后由 ~DeatHMooN~ 于 19-5-2009 04:40 编辑
The thermal envelopeIt's always interesting tomonitor new developments, and for AMD a large problem to tackle waspower consumption. They brought it down severely in 2D (desktop mode).As a results we see very IDLE temperatures at roughly 55 Degrees C (131F), a little on the high side.
Once we start stressing the GPUthe temp goes up big-time, we level at roughly 71 Degrees C (160F). Andthat's just a great temperature really.
http://www.guru3d.com/imageview.php?image=17561
Observe Rivatuner monitor GPU temperature while stressing the GPU.
Noise Levels coming from the graphics card / coolingWhen graphics cards produce alot of heat, that heat usually needs to be transported away from thehot core as fast as possible. Often you'll see massive active fansolutions that can indeed get rid of the heat, yet all the fans thesedays make the PC a noisy son of a gun. I'm doing a little try-out todaywith noise monitoring, so basically the test we do is extremelysubjective. We bought a certified dBA meter and will start measuringhow many dBA originate from the PC. Why is this subjective, you ask?Well, there is always noise in the background, from the streets, fromthe HD, PSU fan etc etc, so this is by a mile or two not a precisemeasurement. You could only achieve objective measurement in a soundtest chamber.
The human hearing system hasdifferent sensitivities at different frequencies. This means that theperception of noise is not at all equal at every frequency. Noise withsignificant measured levels (in dB) at high or low frequencies will notbe as annoying as it would be when its energy is concentrated in themiddle frequencies. In other words, the measured noise levels in dBwill not reflect the actual human perception of the loudness of thenoise. That's why we measure the dBA level. A specific circuit is addedto the sound level meter to correct its reading in regard to thisconcept. This reading is the noise level in dBA. The letter A is addedto indicate the correction that was made in the measurement.Frequencies below 1kHz and above 6kHz are attenuated, where asfrequencies between 1kHz and 6kHz are amplified by the A weighting.
TYPICAL SOUND LEVELS Jet takeoff (200 feet)120 dBA Construction Site110 dBAIntolerable Shout (5 feet)100 dBA Heavy truck (50 feet)90 dBAVery noisy Urban street80 dBA Automobile interior 70 dBANoisy Normal conversation (3 feet)60 dBA Office, classroom50 dBAModerateLiving room40 dBA Bedroom at night30 dBAQuiet Broadcast studio20 dBA Rustling leaves10 dBABarely audible We start up a benchmark andleave it running for a while. The fan rotational speed remainsconstant. We take the dBA meter, move away 75 CM and then aim thedevice at the active fan on the graphics card.
The cooler design itself is anoisy little f*xker, however... ATI keeps fan rotation below 40%... andas such the cooler is silent. We measured 39 dBA from the system. Oncethe graphics card is getting hot by fully utilizing it, we get stuck ata 40~41 dBA measurement which you can hear, softly.
Very nice, but if you decide to manually control the fan for more airflow, above 60% RPM it will be noisy.
Unboxing - Radeon HD 4770 512MBOn the nextfew pages we'll show you some photos. The images were taken at high-resand then scaled down. The camera used was a Canon 450D 12 MegaPixel.
http://www.guru3d.com/imageview.php?image=17571Right then, meet the RadeonHD 4770. This is an engineering / reference sample straight from ATI,equipped with 512 MB GDDR5 128-bit memory clocked at 3200 MHz(effective).
http://www.guru3d.com/imageview.php?image=17569One thing is a fact, itcertainly does not look like a budget card. At sub 99 USD you getRadeon HD 4850 game performance and a dual-slot cooling design, thatquite frankly looks really swell. The cooling design is exhausting hotair outside your PC. Fan RPM is kept below 40% keeping the productquiet.
http://www.guru3d.com/imageview.php?image=17573Backside of the PCB. No memorychips are located here, neither is there space for it. We do expect tosee some 1024MB models in the near future though.
http://www.guru3d.com/imageview.php?image=17568When we place the card into aperspective front view, we stumble into two DVI connectors (HDCPcapable). Both dual-link DVI, thus supporting high-resolution monitors.
http://www.guru3d.com/imageview.php?image=17567When we flip the board aroundonce more we can see CrossfireX connectors located at the top. Intheory it's possible to hook up three maybe even four of these cardsand get them working together, though we advise not using more than twofor best compatibility.
Drivers quickly become an issue when using more than two GPUs simultaneously.
http://www.guru3d.com/imageview.php?image=17574A 6-pin power connector. ThePCIe slot will deliver 75 Watts. Apparently it's not enough for this'budget' card as it needs to feed from another 75 watt source. The TDP(peak wattage) for this card is set at 80 watts.
http://www.guru3d.com/imageview.php?image=17565It's time to insert the cardinto our test-system and see what she does. In a twilight environment,red goes dark... so that makes the overall aesthetics a bit moremysterious.
http://www.guru3d.com/imageview.php?image=17564One final shot. Over the nextpages we'll tell you a tale or two about our test system and softwareused, and then obviously fire off some benchmarks at the product to see what kind of performance we actually get returned. But first, due to the beta drivers we obtained, we need to check up on image quality. DirectX 10.1
Any Series 4000 Radeon product has support for the DirectX 10.1 API, introducing a new layer of extensions. DirectX 10.1 was launched with the Windows Vista Service Pack 1 and is backwards compatible with the existing DirectX 10. Make no mistake, DX10.1 fully supports DX10 hardware. And DX10.0 class cards will still play DX10.1 games just fine.
It's basically an update to DX10 that extends the hardware functionality slightly. All the hardware is still supported, all the games still run, all the features are still there, it's just simply extended the feature set and the lifetime of the API. The release mainly sets a few more image quality standards for graphics vendors, while giving developers more control over image quality. Features scheduled for DirectX 10.1 include:
* Mandatory 32-bit floating point filtering
* Mandatory 4x anti-aliasing
* Shader model 4.1
UVD 2.0
UVD is short for Universal Video Decoder. With proper 3rd party software like WinDVD or PowerDVD you can enable support for UVD (2) which provides hardware acceleration of H.264 and VC-1 high definition video formats used by Blu-ray and HD DVD. The video processor allows the GPU to apply hardware acceleration and video processing functions while keeping power consumption & CPU utilization low.
You will have sheer decoding perfection on both the HD 4850 and 4870. Low CPU utilization whilst scoring maximum image quality. One improvement has been made as well: you can now upscale your 1920x1080 streams fine towards for example a 2560x1600 sized monitor (no more black borders).
New in the GPU architecture of the series 4000 is an updated video engine. It's not much different opposed to the old UVD engine, yet has two new additions for post-processing, decoding and enhancing video streams. Dual stream decoding is one of the new features. For example if you playback a Blu-ray movie and simultaneously want to see a director's commentary (guided by video) you can now look at both the movie and (see it like picture-in-picture) in a smaller screen see the additional content. Obviously this is Blu-ray 2.0 compatibility here, and the additional content is an actual feature of the movie. But definitely fun to see.
A new feature also is Dynamic Contrast Enhancement which was introduced by team green last year.
It does pretty much what the name says; Dynamic Contrast Enhancement technology will improve the contrast ratios in videos in real-time on the fly. It's a bit of a trivial thing to do, as there are certain situations where you do not want your contrast increased. Think for example a scary thriller, dark environment... and all of a sudden your trees light up. So with that in mind; the implementation has been done very delicately. It does work pretty well, but personally I'd rather tweak the contrast ratio myself and leave it at that. Another feature is Dynamic Color Enhancement. It's pretty much a color tone enhancement feature and will slightly enforce a color correction where it's needed. We'll show you that in a bit as I quite like this feature; it makes certain aspects of a movie a little more vivid.
Some like others hate these features. I say it's good to have choices and anything that can enhance image quality is nice to have in my book. Directly tied to the UVD engine is obviously also sound. AMD's Radeon series 3000 and now 4000 cards have a feature that the competition does not have. It can pass lossless sound directly through the HDMI connector. This has been upgraded as it's now possible to have 7.1 channel lossless sound, meaning DTS-ES and all other formats now have become a reality. A very nice move indeed as that distance between the living room and your PC is getting smaller each year. Yours truly for example has a nice Onkyo receiver which I connect HDMI to. This receiver will take that 7.1 channel sounds with a lot of interest, process it, and then passes through the HDMI content itself to the HD television. All that over just one HDMI cable.
With the Series 2000/3000/4000 graphics cards you'll receive a DVI-to-HDMI adapter which, and make no mistake here, will carry that sound over HDMI. That's unlike current DVI-HDMI adapters and cables which do not carry sound. Fantastic if you are watching a Blu-ray movie, simply connect HDMI to your HDTV for PCM sound, or connect it through a TrueHD/Dolby HD receiver and get that sound lovin' going on through that receiver of yours. All with one simple cable.
Again - mind you that to be able to playback high-def content you'll still need WinDVD or PowerDVD, a HD source (Blu-ray player) and a HDCP monitor or television.
CrossFireX
Well, just like NVIDIA's SLI, CrossFire is a situation where you add a second, third or even fourth similar generation graphics card (or in today's case GPU) to the one you already have in your PC and effectively try to double, triple, quadruple your raw rendering / gaming performance.
The idea is not new at all though... if you are familiar with the hardware developments over the past years you'll remember that 3dfx had a very familiar concept with the Voodoo 2 graphics card series. There are multiple ways to manage two cards rendering one frame, think of Supertiling, it's a popular form of rendering. Alternate frame Rendering, each card will render a frame (even/uneven) or Split Frame rendering, simply one GPU renders the upper or the lower part of the frame. So you see there are many methods where two or more GPUs can be utilized to bring you a gain in performance.
Even the more affordable products from ATI are allowed to be linked up with other similar GPUs. Meaning you can pair the 4770 with 2 additional cards to double or even triple performance.
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