One of the drawbacks of the GPUs built into the Clarkdale/Arrandales CPUs and the Sandy Bridge CPUs was the lack of 23.976 Hz for matching 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:

  1. 23.976 Hz
  2. 24 Hz
  3. 25 Hz
  4. 29.97 Hz
  5. 30 Hz
  6. 50 Hz
  7. 59.94 Hz
  8. 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.

However, being in the US (NTSC land), we are looking at the minimum necessary subset here, namely, support for the following:

  1. 23.976 Hz for 23.976 fps source material
  2. 24 Hz for 24 fps source material
  3. 59.94 Hz for 59.94 fps source material

We have observed that the refresh rate is heavily dependent on the AV components in the setup (a card which provided perfect 23.976 Hz in my setup performed quite differently in another). In order to keep the conditions same for all the contenders, the custom refresh rates were tested with the HDMI output of the card connected to an Onkyo TX-SR606 and then onto a Toshiba Regza 37" 1080p TV. The Toshiba TV model is indeed capable of displaying 24p material.

GT 430:

The NVIDIA Control Panel provided a 23 Hz option by default when connected in the test setup. This is obviously coming from the EDID information. Setting the refresh rate to 23 Hz and playing back a 23.976 fps video resulted in the following:

Note that the playback frame rate locks on to 23.971 fps, and the display refresh rate also loosely locks on to 23.971 Hz. Unfortunately, this is only slightly better than the 24 Hz lock that Intel provides for the 23 Hz setting. With this, one can expect a dropped frame every 200 seconds.

Fortunately, NVIDIA provides us with a way to create custom resolutions using the NVIDIA Control Panel, as in the gallery below.

The display mode refresh rate should be set to 23 Hz, and the Timing parameters need to be tweaked manually (altering the refresh rate to change the pixel clock). This is more of a trial and error process (setting the refresh rate to 23.976 as in the gallery below didn't necessarily deliver the 23.976 frame lock and refresh rate during media playback). With a custom resolution setup, we are able to get the playback frame rate to lock at 23.976.

The display refresh rate oscillates a little around this value, but, in all probability, averages out over time. We do not see any dropped or repeated frames.

Moving on to the 24 Hz setting (needed for 24 fps files, common in a lot of European Blu-rays), we find that it works without the need for much tweaking.

Playback locks at 24 fps, and the refresh rate oscillates around this value with very little deviation.

The default NTSC refresh rate (59.94 Hz) works in a manner similar to the 24 Hz setting, as is evident in the gallery below.

MSI GT 520:

With respect to custom refresh rates, the GT 520 is very similar to the GT 430. The 23 Hz setting, at default, had the same issues as the GT 430, but nothing that a little tweaking didn't fix. The gallery below shows the behavior with the default 23 Hz setting:

After setting up a custom resolution, we get the following:

The 24 Hz setting, at default, showed a slight issue with the playback frame rate locking at 24.001 Hz. This would imply a repeated frame every 1000 seconds (~17 minutes).

This can probably be fixed by altering the timing parameters for the 24 Hz setting, but we didn't take that trouble.

Setting up NTSC refresh rates with the 59 Hz native setting gave us the following results, similar to the issue we had with 24 Hz setting.

DDR3 and GDDR5 based 6450 :

We didn't find any difference between the two versions of the 6450 that we tested with respect to refresh rate handling. In this section, we will present screenshots from the GDDR5 based 6450.

Catalyst Control Center automatically enables the 23 and 24 Hz settings in the drop down box for refresh rates by recognizing the EDID information. How well do these settings work? A look at the gallery below shows that the behavior is better than Intel's and NVIDIA's native offerings. However, there is still the issue that the play back frame rate locks to 23.977 fps / 24.001 fps. The refresh rate is not exactly 23.977 either, but mostly below that. All in all, this is not the ideal 23.976 Hz, but something that the 'set-it-and-forget-it' crowd might be OK with.

We didn't get a chance to test the 59.94 Hz settings for videos, because the 6450s' way of playing back 1080p60 videos was to present a slideshow. A brief look at the gallery below reveals the issue:

There is a little bit more coverage about this in the 'ESVP on the 6450s' section.

Sapphire 6570:

While the 6450 was only slightly off from the required 23.976 and 24 Hz settings, the Sapphire 6570 took a little more liberty. 23 Hz gave us 23.978 Hz and 24 Hz gave us 24.002 Hz, resulting in repeated frames every 500 seconds.

The 59 Hz setting for the 6570 gave us 59.946 instead of 59.94, which eventually results in a repeated frame every 167 seconds (~3 minutes).

The takeaway from this section is that none of the GPUs can claim to do fully perfect 23.976 Hz refresh rates. With luck, the ATI card in a particular setup may be able to provide the perfect refresh rate. After all, they came very close to the required settings in our testbed. The NVIDIA cards, at default, are probably going to be always off. However, for the advanced users, there are some avenues available to obtain the required display refresh rate. Unfortunately, there is no way I am aware of to feed custom refresh rates in the Catalyst Control Center.

Before I started the review, it was my opinion that AMD is much better at native refresh rates compared to NVIDIA. After putting the various cards through the paces, I am forced to reconsider. AMD may work well for the average HTPC user. For the more demanding ones, it looks like NVIDIA is the winner in this area because of the ability to create custom resolutions.

HQV 2.0 Benchmarking Cadence Detection : Clearing the Confusion


View All Comments

  • ganeshts - Thursday, June 16, 2011 - link

    PotPlayer apparently doesn't have support for hardware deinterlacing, and has a host of other issues [ Search for PotPlayer in this page and then read the next set of posts about it : ].

    Of course, if it works for you, it is great :) (probably it is a good solution for people watching progressive material only).

    The author of LAV CUVID talks in that thread about how renderless DXVA mode works with madVR at the cost of deinterlacing.

    Btw, there is no decode of DTS-HD in any open source software now. Both ffdshow and PotPlayer can decode only the core DTS soundtrack. DTS decode has been around for a long time, though.
  • NikosD - Saturday, June 18, 2011 - link

    Indeed, I was referring to progressive material only - interlaced material is rare - but the page you mentioned says PotPlayer has CPU deinterlacing.

    I don't see where is the problem.

    Hardware Deinterlacing is less important - for most users - than Hardware Decoding (DXVA) and less important than the UNIQUE capability of using DXVA + madVR at the same time.

    The cost of hardware deinterlacing is nothing compared to the cost of DXVA and madVR.

    For the audio part of your answer, I have to say that because of my AVR (Pioneer VSX-920) decoding inside a PC, BluRay, Media Player or any other decoding capable device of multi-channel audio is never an option for me.

    I always prefer the bitstreaming solutions for multi-channel audio - as most of the owners of AVR do - like those provided by FFDshow and PotPlayer which both are more than capable of providing them.

    That's why I wrote "decoding and pass-through", I had to write "splitting and pass-through".

    One last word.

    For every piece of software out there, there is always a list of changes, bugs, things to do.

    That doesn't mean we don't use it or like it.
  • PR3ACH3R - Friday, June 17, 2011 - link

    @Ganesh T S,
    This is some NICE work.
    In fact, I cannot recall when was the last time I have seen such an in depth article on the HTPC GPU subject in Anandtech.

    The balance between the technical issues, the background, & the effort to honestly report all issues known to you in this article, is spot on.

    If it is missing something on the issues report, it misses on the ATI/AMD DPC Latency spiking issues.

    As this is still remains unnoticed in Anandtech even in this excellent article, here is a link to the AVS post describing it.

    (Ignore some of the discredit attempt posts in this thread, this problem exists to this very day.)
  • NikosD - Thursday, June 23, 2011 - link

    Well, I did some further tests and found out that PotPlayer does have hardware deinterlacing.

    Have you done any tests by yourself to see if the player supports Hardware Deinterlacing ?
  • ganeshts - Saturday, June 25, 2011 - link

    NikosD, I will definitely try PotPlayer out in the next GPU review. Till now, my knowledge is limited to what is there in the AVSForum thread. Reply
  • flashbacck - Friday, June 24, 2011 - link

    I know HTPCs are even more of niche these days than ever, so I appreciate you still doing these tests very much. Reply
  • wpoulson - Thursday, July 28, 2011 - link

    I really appreciate this guide and have been stepping through it

    I just registered the file from TMT5 but the filter is not showing up in the External Filter section of MPC-HC. At first I thought it might be because I registered it on the 32 bit side and I'm using 64 bit MPC-HC, so I unregistered the file from System 32 and registered it on the 64 bit side.

    I registered it by going to Start>CMD>Cntrl-Shift-Enter and using the "Regsvr32" command to register the file. I put the file along with the checkactivate dll in a folder in the root directory of my C drive and pointed the Regsvr command to the file. After hitting enter, I received a "dll successfully registered" message.

    Can someone help me to get the filter visible for MPC-HC?

    A question...While it's considered beta, will the new LAV video decoder do the same thing the arcsoft video decoder does?


  • stuartm - Friday, January 20, 2012 - link

    I am aware the gt 430 is a good choice to work around the infamous WMC 29/59 framerate bug. Can you comment on whether or not the 6570 will stutter or not when playing content with 29/59 framerate problems? A very important consideration for those of us using ceton or HDHR Primes (or the new Hauppauge box) for cable TV Live viewing and record/replay.

    Thank You
  • MichaelSan1980 - Saturday, January 21, 2012 - link

    I'd use my HTPC for DVD's and BD's only with an Full-HD TV. Since i have a rather strong CPU and wouldn't use Hardware Deinterlacing for DVDs, i wonder, if the GT520 is ~that~ bad, in terms of image quality? Reply
  • drizzo4shizzo - Wednesday, June 20, 2012 - link

    Old guy here.

    In the market but I need confirmation that these cards can do component output to "old guy" HDTV.

    NONE of the marketing materials suggest that any recent card can.

    Meaning they either come with a component video breakout or at least are compatible with a known 3rd party product, and that they can do the RGB -> YUV thing.

    This ancient EVGA 7600 GT I have does it... with an "svideo lookalike" 7 pin -> component breakout.

    Anyone? Beuller?

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