Will a CPU upgrade to dual-core Athlon 5600+ be sufficient for 1080p?

My 4-year-old HTPC has a single-core Athlon 64, 2 GB RAM, NVidia 7300GT. It's sufficient for upconverting DVDs and playing music, but now there is so much free and rental/purchase/subscription content out there in 1080p that I want to access but this hardware is not up to that level. And I'm considering adding a Blu-Ray drive next year.

I'm hoping the sole hardware change of a CPU upgrade to a sufficiently fast Athlon 64x2 will be sufficient to make it capable of handling Blu-Ray and other 1080p content. If I need to upgrade the whole enchilada with a new motherboard + faster CPU + new video card, I'll postpone the upgrade another 6-12 months and buy a whole 'nother PC.

The motherboard has socket AM2 and supports up to 6400+ in the AMD Athlon 64x2 line of dual core processors, but I'd prefer to keep it at 5200+ or 5600+ which are 65 watts instead of 89W or 125W for the faster processors.

So, what do you think... would the 5200+ or 5600+ be enough if that's the only hardware change?

Your 5200+ worked great with an equally underpowered video card as mine?

So it looks like the CPU upgrade alone should be good enough for downloaded or streaming 1080p content, but I'll need a better video card for high-bitrate 1080p stuff like Blu-Ray?

If I get a new video card, it would have to be really cheap, otherwise the total cost of CPU + video card + Blu-Ray drive approaches the point where I'd rather just buy or build a whole new machine.

But since I'm not getting the Blu-Ray drive right now, I'll also forget about the video card for now. By the time I'm ready for it, both the drive and video card would be cheaper.

This motherboard doesn't support Athlon II, but the 64x2 5600+ isn't terribly behind the Athlon II X2 240, according to these benchmarks: http://www.cpubenchmark.net/mid_range_cpus.html

Motherboard with CPU options

I wonder what the N/A really means for the lists of AM2+ and AM3 CPUs. Does that mean it simply doesn't work, or is it that it works but the mfr. won't support it (just like overclocking works but isn't officially supported)? At the end of the page they seem to suggest that AM3/AM2+ CPUs would work with the motherboard.

Yes I saw that, but the question is whether "not supported" really means "it doesn't work" or just "it probably works but you're on your own if anything goes wrong".

Similarly, many hardware items are "not supported" under Linux or Windows 2000 according to the manufacturer, even though they actually work with those operating systems.

Nevertheless, I won't be buying and trying any of those "not supported" CPUs unless I see enough evidence of them actually working with this motherboard.

$100 would be about what I'm willing to spend for the CPU + GPU.

How do I know which NVidia cards are capable of sending audio through HDMI? I don't need bitstreaming of HD Audio formats; 16-bit 48KHz 8-channel PCM is fine, but I can't find a list of HDMI-audio-capable cards or chipsets on NVidia's web site or elsewhere, nor does it say it in the specs for each card on vendor's sites.

EDIT: I eventually found this page which has a list of all series of GeForce cards, and then each link brings up a detail page for each chipset which includes the HDMI audio capability. So while there is no master list of HDMI-audible cards, at least I can find out about each card one by one.

Stereo LPCM, or 8-channel LPCM? The detail pages for the 8000 and 9000 series cards only show "SPDIF", so I figured they can't do any better than stereo LPCM (i.e. the same type of PCM that can be sent over a Toslink or coax SPDIF connector).

Thanks a lot for that list! It will be very useful when I'm looking to buy a video card.

But for now, I'm just going with the CPU upgrade alone to see how it does. It along with my existing 7300GT might be good enough for downloadable and streaming hi-def content, which isn't as taxing as Blu-Ray.