AMD Radeon HD 7750 & Radeon HD 7770 GHz Edition Review: Evading The Price/Performance Curve
by Ryan Smith & Ganesh T S on February 15, 2012 12:01 AM EST- Posted in
- GPUs
- AMD
- HTPC
- GCN
- Radeon HD 7000
Custom Refresh Rates with AMD 7750
One of the drawbacks of the GPUs built into the Intel CPUs was the lack of a 23.976 Hz refresh rate to match the source frame rate of many videos. Combined with the lack of reliable support for open source software, this has often pushed users to opt for a discrete HTPC GPU. Ideally, a GPU should be capable of the following refresh rates at the minimum:
- 23.976 Hz
- 24 Hz
- 25 Hz
- 29.97 Hz
- 30 Hz
- 50 Hz
- 59.94 Hz
- 60 Hz
Some users demand integral multiples of 23.976 / 24 Hz because they result in a smoother desktop experience, while also making sure that the source and display refresh rates are still matched without repeated or dropped frames.
With the Sony Bravia KDL46EX720 (the new display in our HTPC testbed) being capable of PAL refresh rates (despite not exposing it in the EDID), we were able to test out almost all the above mentioned refresh rates. The only exception was 60 Hz (which definitely works well in the usual desktop mode, but, was one for which we were unable to obtain a sample file with a matching frame rate).
Using madVR, we were able to judge how often a frame would get repeated or dropped in the renderer due to the mismatched refresh rate and frame rate. With the 23.976 fps sample, we were looking at more than 15 minutes before a dropped frame, while, for the 24 fps sample, we were looking at more than a hour before a frame repeat.
By default, modes not reported in the EDID were not available in the CCC settings. However, it was quite straightforward to display and choose the refresh rates not supported by the monitor in its Windows settings. Some of the other 'native refresh rates' we tested are reproduced below:
AMD's refresh rate matching feature works pretty well most of the time, but it could be made better by giving the user more control over the various timing aspects (maybe in an 'Advanced' hidden menu similar to what is done by NVIDIA). This could be useful for consumers who don't want to put up with frame drops / repeats even once every 20 minutes or so.
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rdh - Wednesday, February 15, 2012 - link
Bingo. But your numbers look at if you were to want to buy today. You might have bought the 5750 or 5770 at a significantly lower cost during a sale in the past 2.5 years. So individual price comparisons may be different than today's prices.IN ADDITION: the 7770 and 7750 require about 3% less power and produce frame rates about 10% higher than their 57xx counterparts. This is after the 57xx have been out for nearly TWO AND HALF YEARS. I purchased both (the 5750 for one system at $65 and the 5770 for another at $99) about 6 months after introduction. Two years later, there is no compelling reason for me to upgrade. That means AMD is only going to be selling these to new desktop purchasers.... a quickly shrinking market. This cannot be good for AMD.
CeriseCogburn - Saturday, March 10, 2012 - link
Since fps is your only metric, itself being a murky and disturbed error filled easily biased mess based upon game set, driver cheating, resolutions, and in game settings chosen, the entire price/perf chart is EPIC FAIL.When your drivers crash, when your game doesn't work, when new games don't work for weeks and months, when dual card drivers are absent, when features like PhysX are no can do - NONE OF IT IS ACCOUNTED FOR....
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Obviously all amd has to do is follow the simpleton idiot fps/per dollar formula for all the stuck cursor gsod fanboys to bloviate and screech they saved 20 cents... then the amd forum masters casn continue to lock them out, lock user problem threads, and smart off that "it's works for them on their eyefinity setup theya re starig at right now"...
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When a crazed, worship filled, religious zealoutry claims the heavens have opened on the cheap and the devil competition has lost all, beware...
Oh.. wait... sorry talking to the wrong person...
Roland00Address - Wednesday, February 15, 2012 - link
I am curious how high these cards will go before they hit the powertune limits.Ryan Smith - Wednesday, February 15, 2012 - link
I'm still writing up an addendum, but here's what I have for the 7770.Ref 7770: 1125MHz core, 4.8GHz memory
XFX 7770: No meaningful overclock on top of XFX's factory overclock. Crashed at 1160MHz core
As for performance, basically look at the XFX card.
Roland00Address - Wednesday, February 15, 2012 - link
Personally I find that the more interesting cardRyan Smith - Wednesday, February 15, 2012 - link
We didn't do any overclocking tests on the 7750. It was necessary to quickly test it in order to be able to ship it to Ganesh for HTPC testing.DarkSynergyt - Wednesday, February 15, 2012 - link
Might be a stupid question but can the 7750 output audio over HDMI? I'm in the process of building an HTPC and this is the final piece to the build.evilspoons - Wednesday, February 15, 2012 - link
My 6570 can and I'm pretty sure they said in the review that it has all the same features as previous generations for video features.ganeshts - Wednesday, February 15, 2012 - link
Yes, it does. With full bitstreaming options too (even WMA Pro). 7.1 channel LPCM support is also there. No worries. (Of course, hot plugging [ say, moving from a direct monitor connection to an AV receiver input ] causes the audio output to act crazy, but that is the case with every card. Reboot fixes the issue)evilspoons - Wednesday, February 15, 2012 - link
This really drives home how obsolete my GTX 285 is. The 7770 has about equivalent performance and uses *130 watts* less.I need a new video card, but I want to see what Nvidia has for us next - I'm not a fanboy (in spite of all my gaming cards since the 3dfx Voodoo 3 being Nvidia), I'm just genuinely hoping for either some competition to drive prices down or something better to blow us away. Come on guys, get a move on already!