NVIDIA GTS 450

Offering 3D Blu-ray (BD) via native HDMI 1.4 and HD audio bit stream support, the recently release NVIDIA GTS 450 represents a drastic shift in the market for discrete home theater PC (HTPC) graphics processing units (GPU). With NVIDIA now providing a feature set unmatched by any vendor we finally have serious competition for discrete space in the home theater. Read on to see if the NVIDIA GTS 450 offers the right balance of power and functionality for your HTPC.

The Card

NVIDIA’s 4×0 family became much more interesting to the HTPC enthusiast when they added support for HDMI 1.4 (i.e. HD audio bit streaming + frame sequential 3D) to the GTX 460/GTS 450/GT 430 (GTX 480/470 do not support HDMI 1.4) GPUs.  The review sample did not include a full size HDMI port so additional hardware was required to connect up to the audio video receiver (AVR) and HDTV.  Mini-HDMI to HDMI and DVI to HDMI adapters were tested with both passing audio and video to the respective device when one cable was used.  Unfortunately, when both cables were connected I was unable to pass HDMI 1.4 (3D) to the TV and HDMI 1.3 (HD audio) to the AVR (audio/video was still passed to the AVR but the TV did not receive either) simultaneously.  Interestingly this did work with earlier drivers (260.63) and is an excellent value-add feature for those with mixed HDMI support in the home theater — hopefully it returns in future revisions.

Like most gaming oriented GPUs, the NVIDIA GTS 450 is a full length PCI-e card and takes two slots with its large heat sink and fan (HSF) as well as requiring an external six pin PCI-e power connection (the PC will not boot with it disconnected).   I was initially concerned by the size of the HSF, expecting excessive noise and heat; as it turned out, the fan was imperceptible during HTPC use so given the necessary space it is quite suitable even in quiet environments.

NVIDIA has historically done a decent job of supporting proper 24p (i.e. 23.976 and 24.000 Hz playback) so I was somewhat surprised to find 23Hz missing in the NVIDIA Control Panel (NCPL) after connecting a 24p capable HDTV (either directly or through the AVR) to the GTS 450, with only 60 and 24Hz modes listed.  The utility does allow for custom resolutions which provides one approach to resolving the oddity, but before pursuing that option there was an additional check.

It is not unusual for the vendor provided user interface to hide some of the supported refresh rates, but I did find it strange that so many of the available options are not exposed through the NCPL.  Ultimately it does not make that much of a difference, only changing the method for selecting one of the more granular options manually: via the “Screen resolution” -> “Advanced settings” Windows provided option.  Automatic methods (i.e. MPC-HC / DTB Addin) and hot-key solutions (i.e. ResChange) query the driver capabilities directly so they are unaffected.

With 23Hz selected, an almost perfect frame rate to refresh rate parity (in blue) was measured with MPC-HC–a FOSS (free open source software) DirectShow based media player–so defining a custom resolution proved unnecessary.  Before moving on, it is also worth noting that for both of these screenshots the MPC-HC video decoder was used to provide hardware acceleration (DXVA2) for decoding the VC-1 and AVC/H.264 content (in purple) used in this test; a significant plus for users of the program.

The NVIDIA GTS 450 supports frame sequential 3D Blu-ray playback with a compatible display.  In my limited testing (I only have two 3D movies) the feature works as advertised with appropriate software, but unfortunately is still a bit too “PC” in execution.

With 3D enabled the driver no longer provides 23/24Hz modes for non-3D playback, so selecting 23Hz via the method discussed earlier actually flips into 24p 3D mode instead of the standard 24p mode which means that in most cases you will only want to enable 3D mode when playing 3D playback and leave it disabled otherwise.  Now let’s move on to an area where execution was perfect.

I love it when things just work so it was really nice to find that the default configuration for colorspace produced perfect video levels (16-235) results for file and disk playback in Media Center, ArcSoft Total Media Theater, Corel WinDVD and Cyberlink PowerDVD while also maintaining proper levels (0-255) for non-video content and passing blacker than black (BTB) and whiter than white (WTW) to aid in calibration.  By default the driver uses RGB 4:4:4 12-bit, but YCbCr 4:4:4 12-bit is also available for those with a display that does not handle RGB input properly.

NCPL does provide an option to force levels, but I found that switching the setting to anything but the default setting — “With the video player settings” — produced inconsistent results between players and content types so it is best not to change anything.

NVIDIA achieved audio feature parity with GPUs from AMD and Intel by adding HD audio bit streaming to the newer members of the 4×0 series.  While it did work most of the time, I experienced several issues while using HDMI audio including: occasional loss of HDCP support (most commonly after resuming from standby or hot plugging HDMI cables) where encrypted BD would not playback and intermittent issues where lossless codecs would not bit stream (switching output to multi-channel LPCM would function perfectly).  Both the HDCP and bit streaming issues were always resolved by rebooting — workable but clearly not ideal.  There is also a consistent issue where the driver does not maintain a persistent connection with the AVR.  Usually this only means that the first few seconds of sound could not be heard as the HDMI audio connection is reestablished, but also occasionally manifested as an issue where audio cannot be heard at all until switching to a different track.

For those who use HDMI but prefer LPCM output, it is worth noting that the audio driver supports 5.1 and 7.1 configurations.  Eight channel audio files played on a system configured in 7.1 output map each channel correctly, but six channel files played on a 7.1 configuration improperly map left/right surround audio to the left/right rear surrounds instead of the correct left/right side speakers.

Compute Performance

Test System:

CPU:	AMD Athlon X2 4200+
Motherboard:	Gigabyte GA-M57SLI-S4
RAM:	4GB(32-bit) / 6GB(64-bit) OCZ DDR2 PC6400
Storage:	OCZ Vertex 2 60GB SSD
Power Supply Unit:	Antec 430W
Case:	Ahanix D4 MCE (Modified)
OS:	Windows 7 Ultimate 32-bit / 64-bit

For those who also play PC games on their HTPC a powerful GPU like the NVIDIA GTS 450 is an essential part of the build.  Unfortunately I am not qualified to evaluate that aspect of the card’s performance, but because my system also spends time transcoding recorded TV files for my phone it was not hard to find a use case to evaluate the extra horsepower it provides.  To test the GPUs compute performance I used Cyberlink’s MediaShow Espresso 6 (a utility that can use NVIDIA/AMD/Intel GPUs to accelerate decoding/encoding video files) to transcode three approximately thirty minute recorded TV files using three different CUDA enabled NVIDIA GPUs (GTS 450, 210 and 8600GT) as well as just the CPU in the test machine.

Not surprisingly, the GTS 450 is significantly faster than any of the other solutions providing a 39% average decrease in transcode time against the nearest GPU competitor (8600GT) and 80% versus just the CPU.  Interestingly the most impressive gain was measured with the most demanding 1080i AVC (H.264) file, taking just over fifteen minutes to convert with the GTS450.  Looking only at these numbers it would be easy to just thank me for pointing out the obvious (you’re welcome ;)), but a quick glance at the power numbers make the full story a bit more interesting.

Taking a look at idle power usage it should first be noted that the “Software” value was generated with the GTS 450 in the PC so of course the values are equal (87W).  Naturally, the performance gain noted versus the other non-Software methods does require more power under load (~44W on average) versus the 8600GT, but when not working it is interesting to note that the slower GPUs idle draw (93W) is six watts more than the GTS 450’s.  It also worth noting that while the GTS 450 consumed more electricity during the run, only the 210 (a passively cooled GPU) was quieter.

A quiet card does not always translate into a quiet HTPC however, so it was important to look at the environmental impact of the GTS 450 as well.  The screenshots above capture the fan (Fan1 = CPU, Fan2 = 60mm exhaust, Fan3 = 80mm intake ) speed and temperature (GPU = GTS 450, Temp1 = case, Temp3 = motherboard, Core = AMD 4200+ X2) of the various components in the modified Ahanix D4 MCE at idle on the left, and 80% of the way through the 1080i AVC transcoding test on the right.  Looking at the results for “Temp1” (circled in the image above) we can see that the GPU has no impact on the case temperature.  I was a bit skeptical however, so measurements were also taken with an infrared thermometer and they confirmed the data from SpeedFan.

Media Performance

To access BD playback ArcSoft Total Media Theater 3, Corel WinDVD 2010 and Cyberlink PowerDVD 10 were tested with the GTS 450.  Each of the three software solutions was able to perform GPU based video decoding, proper 3D BD playback, and bit stream HD audio (TrueHD/DTS-MA) with the latest update installed from each vendor.

Video decode performance was measured with a series of physical BD and 1080p M2TS files containing AVC/VC-1 video and TrueHD/DTS-MA audio with the results captured in the table above.  With each hardware capable decoder, including the free open source (FOSS) DXVA2 enabled MPC-HC decoder, it performed very well with no obvious playback issues.

When evaluating HQV-HD scores it is important to remember that while numbers are produced, the outcome is still somewhat subjective so results should only be evaluated within the context that created them; in this case connected directly to a Panasonic TC-P58VT25.  I was somewhat surprised with the results (PDF with the full breakdown is available here), most notably in the “Noise and Artifact Reduction” section.  Clearly NVIDIA has some catching up to do — not only in noise reduction, but also cadence detection where recent AMD video drivers have a significant lead.  Given the relative immaturity of the 4×0 family, I hesitate to read too much into the score at this time;  the hardware is quite capable so I would not be surprised if subsequent driver versions produce significantly better results over time.

Conclusion

Offering low idle power consumption, impressively quiet operation, full hardware acceleration – available commercially and to the FOSS community – for video playback alongside an unmatched feature set at a reasonable price ($100-$150 street) the NVIDIA GTS 450 provides an unexpectedly good option for HTPC users who need more GPU in the home theater.  By being first to market with HDMI 1.4 3D support and [finally] adding HD audio bit streaming NVIDIA has made the choice for HTPC enthusiasts in the market for a discrete GPU much more complex — in a good way.  I was impressed with the hardware’s capability and see enormous potential for NVIDIA to become a serious contender in the HTPC market as the drivers mature.

Pro:

• Unmatched feature set (HDMI 1.4)
• Powerful hardware
• Quiet
• Power Efficient
• 24p support
• Consistent video levels across players and content type

Con:

• HDMI audio driver needs time to mature
• Enabling 3D removes non-3D 24p support
• Does not support simultaneous HDMI 1.4 (TV) and HDMI 1.3 (AVR) connections

Thanks to NVIDIA for providing the review sample.