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Llano APU for Whole-Home HTPC/DVR/Media Server?

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I tried asking/discussing this in the New Build section, but got no traction. Since my uncertainties are mostly processor related, I figured I'd try again here.

My current Zacate setup doesn't seem quite up to the task I want it to perform, which is record and play/stream multiple (up to 4) simultaneous HD broadcasts. So I'm planning a new build which will house all the video processing (recording and streaming) in one computer and just use players (Xbox, PS3, WD TV Live Plus, etc) in the rest of the house.

The question: How much is the CPU involved in recording / transcoding HD video? Should a Llano (A6-3500 or A8-3800) be enough for what I want to do, or should I go with a Sandy Bridge (i3-2105 or even i5-2405S)? I'm trying to keep the power consumption low if possible, but I'm open to other recommendations. Cost is also a consideration, but not as important as capability and energy efficiency.

More about : llano apu home htpc dvr media server

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Thanks for the reply, Greg. I figured I'd jump for the A6 over the A4 since I get an additional CPU core and twice as many GPU streams for only $10 more and same TDP. I just wanted to make sure I wasn't wasting more money before pulling the trigger. I guess I'll go ahead and build it and see what I get. :sweat:  Worst case I've only wasted $165 for the APU + mobo.

I just wish the Hudson D3 (A75) FCH supported RAID 5 onboard. I could wait for the socket FM2 APUs and see if the Hudson D4 releases with this capability, but AMD's roadmap originally paired it with the cancelled Komodo processors, so I can't tell if they'll get made and even if they do I'd have to worry about higher cost for a Trinity processor and D4 board. No perfect solutions without a crystal ball. :??: 
CPUs Master

Whats your worste case scenario? Streaming 4 HD streams while recording 4 and transcoding 4 in the background?

Most recording , like from a tuner card is a peice of cake cpu-wise as basically the file is just copied to the hdd as it comes in.

Streaming is light on the cpu most of the time also as it is more network intensive and I'd recommend you break your network into 2 segments with 2 gigabit nics in the server feeding the segments (1 nic per segment) and sperating your heaviest loads onto the seperate segments. You'll also need fast and capable harddrive system as 4 streams would be about 120mb/s. A Raid 0 or 10 array should do well unless your planning on recording at the same time as streaming; then you might need to go raid5.

Transcoding will kill your cpu. Well not literally but it will peg it to 100% making all other funtions slow as heck. Hopefully you'll schedule this to happen when no one is using the system. With transcoding the a8-3850 does ok and can almost keep up with a phenomIIx4 965 to give you an idea of its performance.
CPUs Master

The dual core Intel Core i3-2105 is actually a bit quicker at encoding video than a quad core AMD Llano A8-3850. Drop in a Core i5-2405 can the difference can be substantial.

A8-3850 vs. i3-2100
http://www.anandtech.com/bench/Product/399?vs=289

A8-3850 vs. i5-2400
http://www.anandtech.com/bench/Product/399?vs=363

If you scroll down towards the bottom of the above links you can see that during the 1st pass of X264 video encoding both Core i3 and i5 CPU consumes a little less power. Not only does the A8-3850 use more power for encoding (at least according to that one single power measurement), it would also need more time to encode since the CPU core is slower. That means even more power. Realistically, the electricity cost between the A8 and i3/i5 is small. The i3 uses 16w less power and the i5 uses 8w less power. Assuming both A8 and i3 PCs are turned on 24/7 for a month (30 days) the A8 will use about 11.5KW more power than the i3. Assuming you pay $0.10 per KWH, the difference is $1.15 per month or $13.82 a year. Assuming a more realistic 6 hours per day, the difference in one month is $0.29 or $3.47 per year.

As for stuttering, I have never really researched any specific HD playback issues with the Intel HD 3000. If you have a limited budget then simply get one of the Core i3/i5 CPUs with the HD 3000 graphics core, then save up money for a video card if you notice any issues. Or get buy a video card that will allow you to watch HD video without any issues.

If you decide to buy a video card for whatever reason, I recommend the following Radeon HD 6450 for $35 after rebate. It does not use much power, probably around 25w under full load (i.e. attempting to play games) or around 16w when playing videos. That's based on similar budget Radeon HD video cards.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

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popatim said:
Whats your worste case scenario? Streaming 4 HD streams while recording 4 and transcoding 4 in the background? ...
...
Streaming is light on the cpu most of the time also as it is more network intensive and I'd recommend you break your network into 2 segments with 2 gigabit nics ... A Raid 0 or 10 array should do well unless your planning on recording at the same time as streaming; then you might need to go raid5.


Worst case scenario currently is Streaming 2, Recording & Transcoding 4, but assuming 4 each would be beneficially conservative for design. Preferably the transcoding would be on-the-fly. In fact, ideal operation would be similar to a modern DVR where the program being watched/streamed may be the same one being recorded & transcoded. But that would require a different user-end solution than my current plan of playing the recorded shows from a player like WD TV Live Plus; each TV would require its own light HTPC to run the MythTV frontend program.

Would "teaming" a second LAN card, or a separate LAN card with "teamed" dual NICs, provide the same throughput capability as what you described without using separate MACs and physically dividing traffic, or is there another logistic benefit to your recommendation? I would like to go RAID 5, but HDDs are currently too expensive. I'll start with a 2x2TB RAID 0, then figure out how to transition to a RAID 5 when disk prices come back to earth.



jaguarskx said:
The dual core Intel Core i3-2105 is actually a bit quicker at encoding video than a quad core AMD Llano A8-3850. Drop in a Core i5-2405 can the difference can be substantial.
...
If you have a limited budget then simply get one of the Core i3/i5 CPUs with the HD 3000 graphics core, then save up money for a video card if you notice any issues. Or get buy a video card that will allow you to watch HD video without any issues.


You seem to be implying what I thought might be the case, that the CPU is heavily involved in the transcoding. I do not intend to play anything directly from the server to a TV; all playing/decoding would be done by the remote machines (WD TV, PS3, Xbox, etc). So if transcoding is CPU-intensive it sounds like a Core i3/i5 with IGP is my best solution, or does transcoding also use enough GPU resources that I should also throw in an entry-level video card like the one you suggested?

Also, as to which processor to get, is the i5 worth the nearly double price tag, or could I stick with the i3? Does hyperthreading make up for the fewer processor cores (specifically related to intended purpose), or is the larger L3 cache on the i5 more important? Also, since I can get a mobo with energy-saving processor control is the lower TDP on the i5-2405S worth the hit to clock speed vs the i5-2500K?




Thanks again for your replies! I know some of this information is tabulated in reviews and comparisons, but I'm not exactly sure which numbers are important in my situation, and they don't typically explain it well enough in the reviews.

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CPUs Master

Not many video encoders can use the video card to assist in encoding video. Of the ones I briefly looked into sometime ago, the Avivo (AMD) and CUDA (nVidia) encoders did not offer many options to customize your encodes. I use HandBrake which only uses the CPU, it is utilize multiple cores and it can also take advantage of Hyper Threading.

The thing about CPUs is that they have SpeedStep (Intel) or Cool 'N Quiet (AMD). Both technologies lowers the clockspeed when there is not much activity which helps reduce power consumption. Is getting an i5-2405S worth getting over an i5-2500k for energy saving purposes? That depends on how you look at things...

The i5-2405S will likely use less power than the i5-2500k, but it will take longer to encode a video which can negate any power savings. The i5-2500k can be overclocked with a P67 or Z68 motherboard which can reduce the amount of time it takes to encode a movie. Assuming you set the video encoding program to shut down your PC as soon as the encoding is done, the overall difference in power consumption may not be much.

The difference in power consumption between a Core i5-2405S, i5-2500k (stock speed) and i5-2500k overclocked will probably be around $1 per month at worst assuming $0.10 per KWH and 6 hours per day of usage. I'm sure realistically it will be about half that.

Also note, that the more "deluxe features" a motherboard has, the more power it will use. So if you buy a motherboard with FireWire, but you don't use it, the circuitry still pulls some watts. I think the difference between your average basic motherboard (~$85) and a super premium motherboard (~$250+) is like going from 35w to 60w.

If you are really, really concerned about power consumption, then you should look at other things around your home that are power hungry. If you live in an 600sf apartment, then you will likely have less electrical devices than if you live in a 1500sf house. The single item that probably uses the most electricity in any household will be the refrigerator. The older it gets the less efficient it will be. HDTVs are probably next especially if you have a plasma TV. Next up is the air conditioner, if you live in a year-round hot area, then it can probably be your most power hungry device at home.

Getting back to your PC, the best thing to do to reduce power consumption is to buy a power supply (PSU) that is rated at 80Plus. Basically that means at any level of power consumption the PSU should be 80% efficient. Assuming all the components in your PC draws 150w of power, the efficiency of the PSU affects how much is drawn from the AC outlet. An 80% efficient PSU means the PSU will be pulling 187.5w from the AC out. 150w is used to power all the components and 37.5w is wasted as heat and noise. The most efficient PSU you can buy is rated at 80Plus Platinum and I believe it is around 92% efficient. With the same 150w load, this PSU would only draw 163w from the AC outlet, thus the wasted power is only 13w. Be aware that 80Plus Platinum PSU are expensive and are usually made for high wattage PSUs (like 700w+) which is more capacity than what you need and the price you pay for such a PSU will likely not be made up for by the amount of electricity costs you save.

jaguarskx said:
A8-3850 vs. i3-2100
http://www.anandtech.com/bench/Product/399?vs=289

A8-3850 vs. i5-2400
http://www.anandtech.com/bench/Product/399?vs=363


Based on your references to these comparisons and other comments made in your post, I have whittled it down to looking at the following comparison charts:

SYSMark 2012 - Overall, SYSMark 2012 - Media Creation, DivX Encode, x264 HD Encode tests and benchmarks, WinRAR 3.8 Compression, and Load & Idle Power Consumptions

Now that I've had more time to research MythTV (my intended PVR application) it looks like this media server will only run the "backend", which requires little graphics capability. Unlike using Xbox 360 as a WMC extender (graphics are pre-decoded by WMC computer and streamed to Xbox), MythTV's "frontend" terminals process and render the videos themselves. The same will be true while I'm just streaming the pre-transcoded video file to a WD TV Live Plus box which does the rendering. So that further encourages that I will be able to do without a discrete video card in the server.

I'm thoroughly convinced at this point that a A6-3500 will not do what I need. The comparison between A8-3850 and i5-2500K shows about 50% improvement in coding benchmarks from A8 to i5, but the price premium is about 80%. I think I'll go with this A8-3870k and ASUS F1A75-V PRO combo which will likely perform what I currently need (correct me if I'm wrong), and spend the savings on other quality parts (case, SSD & HDDs, UPS) that have longer product lives. I might also check into the pricing of a 6- or 8-core Bulldozer build with a low-power video card, but I'll flesh out that consideration tomorrow.

BTW, my AC and fridge are both less than 3 years old and every light in my house is a CFB. ;)  I am still using a plasma TV, though. :p  I already got a Rosewill HIVE-650W modular PSU for this build which is 80+ Bronze certified, and the mobo listed above combines good performance with excellent power management, according to this review.
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