Jim Scarbrough
Forum Replies Created
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I’ve been going through the same thought process. After much research, I’m in the process of upgrading my computer with a Core i5-2500k, H67 mobo, 8GB DDR3 RAM, and Win7 64.
The +50% price bump for the i7-2600k generally only provides a 5-10% improvement in render times. On one specific render test, the 2600k was actually 10% slower, though on another it was >20% faster.
As always, the law of diminishing returns applies. For a video pro doing a lot of rendering, a 5-10% boost might be well worth an extra $100.
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Dave – you already answered the HT question in another thread:
https://forums.creativecow.net/thread/24/918270
Anyone reading this thread will want to read that one as well. Lots of great info.
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David: Your April 7 post started me researching the Sandy Bridge processors and I’m now in the process of upgrading with an i5-2500k/H67 combo. (H67 just in case Sony adds QuickSync support to Vegas!)
Everything I’ve read indicates that HyperThreading slows down most rendering engines, including Vegas. Do you have HT enabled or disabled? If it’s enabled, could you try disabling it and rendering your test clip? I think it would be valuable info to those reading this thread.
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Vegas 10.0d will leverage AMD GPUs when it is released any day now (5/2011); it’s a free update for current Vegas 10 customers.
Despite possibly seeing some rendering speed increase, I would recommend avoiding the use of CUDA acceleration as reviews have shown it to have a major negative impact on video quality. AMD OpenCL render acceleration has less benefit on render times, but doesn’t have nearly as much impact on the quality. Either way, you might test it on a short clip and upload that clip to YouTube to see if the end result is worth whatever gains in rendering you might experience.
Intel’s QuickSync isn’t supported on Vegas yet, but has a ginormous impact on rendering times with minimal effect on quality. Vegas didn’t seem to leverage CUDA very well according to user posts here and on other forums, so it remains to be seen if AMD acceleration will provide benefits to anyone except those using a very weak CPU + high end GPU – an unusual combo, to say the least.
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It might be better that Vegas 10 doesn’t leverage the GPU more, seeing as they’re using the CUDA API.
AnandTech and TomsHardware have recent articles with good info on the current GPGPU rendering technologies – Nvidia’s CUDA (as used by Vegas 10) and ATI’s Stream. Although CUDA was faster than Stream, it seems to generaly produce noticeably worse video quality to achieve that speed. The article is focused on Intel’s QuickSync technology, which holds great promise. https://www.anandtech.com/show/4083/the-sandy-bridge-review-intel-core-i7-2600k-i5-2500k-core-i3-2100-tested/9
One interesting comment in the article, “Both AMD and NVIDIA have fixed function video decode hardware in their GPUs now; neither rely on the shader cores to accelerate video decode.” The article mentions that the same hardware used to accelerate decode is also used to accelerated decoding. So a lower-end card should provide similar benefits to a higher-end card with more shader units, leaving only the amount and speed of the video card’s RAM as a variable.
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David – Have you tried moving your swap file to a 3rd HDD? One not being used by the system/program and not being used to write the rendered file? I would guess the RAMdisk was being used this way, so the lack of improvement there probably answers my question – and kills my hopes…
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@David Keaton – just saw your rig specs in another post and your GTS 250 does indeed have 1GB of RAM. Although it’s probably DDR3, it should still provide a bump in rendering speed to Sony’s AVC codec. I’ve been considering upgrading to Vegas 10 and a GTS 450 primarily for this feature and am now having serious doubts.
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Sorry to interrupt the RAID discussion, but to get back to the original post…
The GTS 250 generally came with 512MB of DDR2 or DDR3 RAM. From my research, you need a bare minimum of 768MB of DDR3, but to be safe, consider 1024MB of DDR3 the minimum.
It also appears that DDR5 will provide faster results than DDR3, but more than 96 CUDA cores won’t necessarily provide an improvement in render times.
So, as often happens, your comparison is flawed, but only because Sony has elected to not provide any guidance regarding optimizing the GPU rendering of Vegas 10.