I7 CPU using PPro CS4. Why so slow?

[Rob Johnson]

Hi all,

I use PP4 to edit my AVCHD files under Windows 7 (64 bit).

I've been looking for the answer to this since last year and as of yet haven't found an answer.

I'd like the simple answer to this; why does PP4 (or more specifically Adobe Media Encoder) encode video SO slow under the i7?

It consistently uses only 25% of my CPU's processing power. Only 25%! This is on a quad-core i7. Usually only two of the cores are running at around 50%, hence 25% total. That means I'm rendering video at about 1/4th the speed. It could be rendering about 4 times faster if AME utilized all 4 cores better. At least AE gives you the option to utilize all 4 cores in the preferences. This is putting me in slow-ville. I feel like I have a Formula One car being driven by Hervé Villechaize.

So what's the dirt? Why does this happen and is there any way I can remedy this situation? Thank you.

[Battle Vaughan]

I don't know, but have a suspicion the preferences > general >optimize rendering for memory / performance option might be involved. Might be worth a comparison test? / Battle Vaughan

[Harm Millaard]

Most likely the CPU is waiting for other components/processes/services to finish, thus sub-optimal performance. Every brand system is crippled from the start. You have to optimize each system for performance.

[Rob Johnson]

I have PP4 set for optimal performance. It isn't really PP4 where the bottleneck is occurring but rather Adobe Media Encoder.

As far as system processes, I shut everything down except for critical system processes (which usually can't (and shouldn't) be shut down). At the time just before rendering, Sytem Idle is probably the only process using any noteworthy CPU power, and which naturally would end once rendering begins.

Sometimes I run an old version of AVISynth to encode video files to x264. And when I do, all 4 cores are going balls-to-the-wall at 100% and I pump out encodes in record times. The same goes for some other programs. So if this this old, crusty version of AVISynth can make the cores talk to each other properly and fully utilize the CPU, I'd think AME CS4 would be able to do the same.

This is not a hardware problem, it's an Adobe problem. One which they should, IMO, give high priority to correcting. After we've fully and painstakingly optimized our system/software/hardware/plugins for CS4, it's yet another hook to get us to move to CS5.

[Harm Millaard]

It may be an Adobe problem if others can replicate this behavior. I for one can not. I have no trouble getting all cores at 100% during encoding. Therefore my conclusion is it is something in your setup, not an Adobe problem.

[Rob Johnson]

There are complaints of this strewn across the net in various forums. I'd be happy to post the links. Specifically, users with I7 processors trying to use AME CS4. Clearly the problem is far from unique to me and my system alone, and much more universal.

Since Adobe Media Encoder CS4 is working so well on your I7 computer, perhaps you'll be good enough to share with us what your work flow is and specifically how your system is set up.

[Harm Millaard]

This is my setup and my workflow is usually XDCAM/HDV/DV with 5.1 sound exported with AME to H.264-BR/MPEG2-BR/MPEG2-DVD/MPEG2 I-frame 1920x1080 for further encoding with HC.

I suggest you try the PPBM4 home page benchmark and mail the results to Bill to see where your system performance is in relation to others. Maybe that will give an inkling of what is going on.

[Pete Bauer]

Thanks for posting your system info, workflow, and Bill's PPBM4 link again for the umpteenth time, Harm. Just speculation on my part, but most people don't have the super-speedy RAID setup that HARM has. I wonder if on some systems the h264 encodes are actually limited by disc write speed rather than processor as one might normally expect?

Rob, you'll help others help you if you give more info about your system including amount of RAM, any overclocking, hard drive set up (inlcuding RAID), scratch disk config. For instance, if you're doing everything on a single 7200rpm HDD, expect poor performance regardless of processor. BTW, your DVinfo user profile says you're using PPro CS2.

[Rob Johnson]

Pete, I'm running Adobe Creative Suite 4 under Windows 7 64 bit, on a quad-core I7 processor, each core clocking at 2.6GHz. I have 12GBs of RAM. There are two 7200RPM HDDs, One for the OS and the other for video files and as a scratch disk.

On Sisoft Sandra 2009, my system components pass benchmarks with flying colors.

I'm not doing uncompressed video. I don't deal with Terabyte sized video files. So how can disk write speed be a factor? If I were trying to write a sustained 100-200MB/sec to the drive I could see the problem, but I'm not writing at nearly a fraction of that speed.

On my last encode, I was encoding an edited AVCHD clip to a Quicktime MPEG4 video file, 1920x1080 at 15Mbit/sec data rate. The final size of the QT MPEG4 file was 900 MBs and took around 40 minutes to render. I get about the same speed as that using my nearly 7 year old Pentium 4. C'mon, doesn't that just wreak of something wrong?

And as I stated above:

"I run an old version of AVISynth to encode video files to x264. And when I do, all 4 cores are going balls-to-the-wall at 100% and I pump out encodes in record times. The same goes for some other programs. So if this this old, crusty version of AVISynth can make the cores talk to each other properly and fully utilize the CPU, I'd think AME CS4 would be able to do the same."

So obviously my system is not inherently "crippled," at least until it comes to AME 4. How is it that AVISynth and other programs can bang the needles on all CPU cores, and yet AME 4 crawls like a snail through a cold, dry garden?

[Harm Millaard]

Unfortunately those flying colors turn to black and white when editing. 2 disks is not enough for comfortable editing as you experience. Your CPU is waiting for the disk to store the temp files, do housekeeping, and a lot of other things and while waiting it has nothing else to do. Hence the 25% figures. The disks seem to be your bottleneck. Running the benchmark I previously pointed you to, may help to identify the bottleneck in your system.

[Roger Keay]

I have experienced encodes with 15% -20% CPU utilization in the past but the issue seems to have been resolved. I use a computer with an i7 920 processor, 6 GB RAM, system C drive and a pair of 500 GB 7,200 rpm drives configured as a RAID using the hardware on the Asus motherboard. The machine runs Vista 64 Home Premium and CS4 4.2.1 with both the OS and application kept current. I do not have anti-virus software installed as the machine is only used for media applications. AME is version 4.2.0.006

At present, I have approximately 80% CPU utilization with AME for H.264 and MPEG2 encodes. The source projects use the HDV preset. The task monitor display shows the 4 physical, 8 virtual hyperthread processors running at close to the 80% mark on average. There doesn't seem to be any problem with disk access which typically runs below 5 MB per second with both the source and destination file on the RAID. This morning I did a test encode. A 112 second HDV project encoded using a standard AME MPEG2 1440 preset and Dolby stereo audio in 94 seconds (84% of program time). The same project output as H.264 took 262 seconds (2.4 times program time). I also tried a Cineform 1440 by 1080i project to Blu-Ray MPEG2 that yielded an encode time of 2:56 from a program length of 3:49 (77% of running time). Cineform decodes take less CPU time than HDV which probably accounts for the 77% of running time versus the 84% with an HDV project.

I have a reasonable knowledge of computers but I am far from being an expert. The computer is not overclocked and I have not done any performance tweaks to increase speed.

[Adam Gold]

Harm, would it be possible for you to post a screengrab of your scratch disk setup page as well? Your system info is really useful and much appreciated.

[Steve Nelson]

Hi Rob,

Ideally you would want at a minimum separate physical disks for source and destination when rendering. A good minimum system has an OS/Apps drive, an audio/video source drive and an a/v destination drive. Of course you can get fancier with RAID etc but at a minimum three drives is a good baseline system.

I'm running a setup similar to this currently although I have external eSATA drives that I can go mobile with as well and bring back to be processed. They're useful for multicam gigs with other operators. I'm also running an i7 920 system with 12Gb RAM, 2 1Tb internal drives and a 1Gb NVidia Quadro FX 3800 video card. I overclock the i7 to about 3.2Ghz and get excellent render times even when using Magic Bullet Looks which is notorious for glacial renderings.

[Rob Johnson]

Roger, I am fully updated and running the same version of PP and AME as you. I was running Vista 64 before I went to Windows 7, and was having this same problem with everything running under Vista 64. So I think the OS can be ruled out. It would be the least probable suspect anyway.

Aside from your RAID configuration it sounds as though our systems are similar. 80% CPU utilization is quite good and, at least in my opinion, would be considered satisfactory compared to my current measly 25%. By chance have you ever worked with or attempted to encode AVCHD files?

[Rob Johnson]

Steve, thanks for your input. I understand what you're saying about drives. Even when I was running 3 drives (OS-Apps/Source/Destination), I was still experience the same problem.

And if you take into account everything I've said in previous posts to this thread, I fully do not believe that the drive situation is the problem. If it was, it would have been flushed out before. When I render, my drives are barely doing anything, as if they're waiting for AME to hurry up.

Also there is the inconvenient fact the AVISynth, and almost every other video app I use, makes full use of the processor. 100% or near 100%. Even the After Effects renderer does much better. That's the elephant in the room that cannot be escaped.

It is this that leads me to believe the it is AME specifically that is not playing well with my I7. However this does not rule out other things, such as the AVCHD codec potentially.