PCI-E vs AGP8x Question (video capture performance)

[Chunkz]

I am looking for some performance benchmarks of people playing games while using Fraps to record the game play. Do any exist?

The reason for my query is the following:
Many many months ago, I was looking to use FRAPS to record video of myself playing an MMO so that I could turn them into movies and show people how great I am. (that's sarcasm )

My problem was, that at 1600x1200, when I turned on the video recording, my FPS was dropping down into the 6-7 FPS range, basically making the game unplayable.

Fraps has a neat feature that lets me record at 1/2 my video resolution, thus changing my 1600x1200 source into 800x600 video stream that is being written to disk. This means that I should get very decent performance, despite the large source (a fast hard drive helps a lot, but 7200rpm should be fine for 800x600 recording)

But using the 1/2 resolution option, I was STILL getting 6-7fps, if not lower. I was perplexed. I turned off sound, I did all sorts of things to try and improve performance of the recording. What's the point of recording my game play if I have to change my resolution way down and make it difficult to enjoy actually PLAYING the game?

In the end, I emailed the Fraps developer, and was suprised to find out that AGP8x, which we all hear is MILES away from being a bottleneck, was actually limiting my frame rate. It seems that AGP is not very happy sending 2 way traffic down from the video card to the PC. Also, while fraps records at 1/2 the resolution, the 1600x1200 source still gets sent across the the AGP bus before being reduced by fraps. This huge amount of traffic was choking my AGP8x bus.

This brings me to where I am today. I currently have a decent, if last generation, system. I'm looking for some confirmation that FRAPS recording performance improves with a PCI-E based system at high resolution. I can play all my games fine, and if PCI-E doesn't solve my bandwidth issue, I'm probably 6 months at LEAST away from upgrading everything. If PCI-E DOES make games at 1600x1200 recordable, I'm tempted to upgrade much sooner.

Has anyone used fraps with a PCI-E based board to capture video at 1600x1200 (1/2'd for writing of course)?

 

[MercenaryForHire]

Welcome.

In your specific case, I'd suggest an external capturing device rather than doing an overhaul to PCIe. Unsure what if anything can capture 16x12, or what you need this for, but I'm interested.

- M4H

 

[Chunkz]

Well that's just the thing - I'm poor.

I actually did do the research on a scan converter, but almost all other solutions involve output going to a video camera (200 bucks for the low end converter, then 4-6-800 bucks for a video camera) or even outputting to another pc means capturing with a TV card that's limited to 640x480 which is kinda "meh" and means more hardware purchases for my other PC as well as the scan converter/splitter.

The big thing is that I'm recording at 800x600 as a goal, so it's not that high. But the AGP bus still has to pass a 1600x1200 signal to the CPU/Fraps program, and that's my bottleneck (or so I'm told, I'm looking to prove/disprove this). Writing 800x600 to disk isn't that bad. 1600x1200 to disk is insane and would probably require some serious RAID'd SCSI drives to pull off

Thanks for the welcome as well, nice to be here

 

[VirtualLarry]

Originally posted by: Chunkz
But using the 1/2 resolution option, I was STILL getting 6-7fps, if not lower. I was perplexed. I turned off sound, I did all sorts of things to try and improve performance of the recording. What's the point of recording my game play if I have to change my resolution way down and make it difficult to enjoy actually PLAYING the game?

In the end, I emailed the Fraps developer, and was suprised to find out that AGP8x, which we all hear is MILES away from being a bottleneck, was actually limiting my frame rate. It seems that AGP is not very happy sending 2 way traffic down from the video card to the PC. Also, while fraps records at 1/2 the resolution, the 1600x1200 source still gets sent across the the AGP bus before being reduced by fraps. This huge amount of traffic was choking my AGP8x bus.

Yes. Normally, all video "surfaces" as manipulated by the game, are stored in video memory on the card itself. AGP is mostly a "one-way" bus, it's like an 8-lane wide highway for traffic, but only in one direction, and the only option for reverse traffic is a sidewalk alongside the highway. PCI-E promises to be a bi-directional two-way highway, which should improve things significantly. I don't have a PCI-E system, though, so I can't really comment. Doing real-time video recording (of anything, not just games) at 1600x1200 is going to be very taxing on a system.

I would suggest, if there's any way to use a video card with an associated secondary TV-out port, to use that, and then either use a capture card in the same PC, or a hardware MPEG-2 capture device, or a seperate computer system entirely, to do that capturing. I suppose it depends though, if you need the text to be readable in the videos, because text on a 1600x1200 screen downconverted and NTSC-digitized or MPEG-2 compressed, definately won't be readable at all.

You might try: 1) running at a lower resolution while both playing the game and recording, and 2) trying to use some "tweaking tool" to force the game to use system memory video surfaces rather than video memory ones. This will make the game play significantly slower, but will allow FRAPS to run faster. I'm not sure offhand how to go about doing that, possibly PowerStrip or another video-card-tweaking tool. There may be game-specific hidden debug switches to do the same thing too.

 

[Chunkz]

Awesome, at least confirmation that the AGP8x thing may be the limitation on the bi-directional traffic issue.

Ultimately, I'm a hobbiest and while it would be fun to make movies, I cannot justify spending all sorts of money to do it "properly". But I was curious if PCI-E would make even running at 20fps doable. I can live with 20fps in game if it's only while recording. 7fps is just too low