My current system has a GTX750 in it and I'm simply not impressed with how my system is handling whether it's rendering or previewing (when editing multiple cameras). I have to prerender my timeline to be able to edit, and rendering is consistently about 3-4x the size of the rendered region.

My target formats are:

1. DVD (yup). Mainconcept MPEG2 encoding, Good or Best quality (used to be "best" but honestly I don't see much of a difference). I use a constant bitrate which I compute based on media size to maximize quality and jussst fit on the disc (DVDA always tells me it won't fit until it's done prepared the DVD and then it always fits).
   
   I use constant because years back I found lots of interlacing and quality issues during fast-moving scenes if I used a variable encode, not to mention multi-pass encoding = less sleep for RedRob ;-)
   
   On my main editing box, I DISABLE my GPU before rendering; it's the only way for me to get it to complete reliably through the night (although at least when it doesn't, I can get a "no rerender required" catch-up)
    
2. 720p or 1080p - When I render for client delivery on Vimeo, YouTube or Dropbox, I use Sony AVC/MVC with the "Internet" templates as a starting point
    
3. Sony MXF 720p - I use this to pre-render my multi-cam 3x3 video so we can edit it at full framerate instead of 3-10 fps. Today I tried out the "Proxy" features of Vegas and it's working well so far! :-)

So you're saying CF will do *nothing* for me, and I should save the $95, eh?

CF won't, a second GPU will but only if you have a system with more then 32 PCIe lanes, socket 2011 and higher.

If you don't have the right system for two, get a RX480 with 8GB if possible.

Keep in mind that you need a bigger power supply to handle two cards and a system that can handle 2x PCIex16; meaning a CPU with minimum 32 PCIe lanes.

Do you really think Vegas needs or uses greater than 8GB/s bandwidth per GPU. 8GB being PIC3 x8.

Video cards with dual GPUs are effectively running x8 per GPU as the GPUs are independent.

The cyberpowerpc folks don't offer the 480 anymore.. 470 4GB yes. As well as 580. Also the 470 crossfire.. it is two GPUs as I understand it, ya? I've configured with a 700W power supply which should easily power it.

Honestly, despite me having been a CS major and very computer savy, today talk of PCI "lanes" just makes me think "I don't have time to understand it all." I need to know..

Will it be stable?

Will it improve render and/or preview speeds in Vegas?

For 95 bucks I would get it if the answer to both were "yes".. still unclear on recommendations

*sigh*

Will it be stable?

That completely depends on the components used, brands do make a difference. My system was as stable as it was with one card but I have a 1200W PSU and a socket 2011 CPU.

Will it improve render and/or preview speeds in Vegas?

Render speeds will improve but by how much entirely depends on the FX used and codec used for encoding.

Sorry, but there is no clear answer.

Keep in mind that you need a bigger power supply to handle two cards and a system that can handle 2x PCIex16; meaning a CPU with minimum 32 PCIe lanes.

Do you really think Vegas needs or uses greater than 8GB/s bandwidth per GPU. 8GB being PIC3 x8.

Video cards with dual GPUs are effectively running x8 per GPU as the GPUs are independent.

There was a significant difference when I ran the two GPUs in x8 vs x16 mode, a good 30%.

Your GPU interface speed should be looked like this:

• System Memory - 20-50GB/s
• PCIe 8x v3.0 - ~8GB/s
• PCIe 16x v3.0 - ~16GB/s
• RX480 GPU Memory - 256GB/s

Does anyone see the bottleneck?

That does not even take into the fact most do not consider they are running V1 or V2 of PCIe which is even slower.

• PCIe V1 X16 - 4GB/s
• PCIe V2 x16 - 8GB/s

You can half those figures if you are running your GPU in 8X mode.

If you want to run 2X GPUs in your system, you need to choose the right motherboard with enough PCIe lanes to support full 16x speeds for both GPUs.

8GB would seem to be the new minimum for GPUs these days. Resolve has an 8GB minimum. Vegas may or may not use all that memory, but most will switch to resolve and then complain on that forum that resolve does not work or is not stable. ;)

"Do you really think Vegas needs or uses greater than 8GB/s bandwidth per GPU"

Yes I do.

(60(128(4096*2160)))/8 = 8.5GB/s for 4K uncompressed @ 60fps

Triple that figure since you are sending uncompressed frames back and forth for OpenCL, and again for display using one card.

1920x1080@60p x 3 = 5.9GB/s

There is substantial bandwidth reduction and overhead on PCIe V1 and V2 so you need to account for that. Also there is bus contention to allow for. So basically you need to massively over engineer the problem to give yourself enough room to maintain smooth frame flow. Another way to look at it is, you need to process frames so fast that you allow for codec decompression, effect render times, and still be faster than 30-60fps.

"The cyberpowerpc folks don't offer the 480 anymore."

As far as I know, the RX580 is basically just a V2.0 of the RX480 that is re-engineered to use less power. I would opt for the RX580-8GB over the 470.

I would have gotten the RX580 w/8GB if it weren't for folks posting on here that it crashes in Vegas unless you stand on one leg and hop up and down chanting praises to Zeus.

So I purchased the system with a single RX470, 4 GB RAM in it because that's what it offered.

I must say -- I'm a bit disappointed with the voices of shared knowledge here on the forum. Conflicting information clouds guidance to those (read: me) seeking information on the basic question: "what will help Vegas 14 perform best for preview and for rendering to format A, B and C?"

Person A -- NVIDIA cards won't perform as well as AMD. Don't get NVIDIA
Person B -- Mix NVIDIA and AMD for best performance
Person C -- Don't get AMD RX580 or other series due to bugs. They won't work well with Vegas and will cause headaches. Only get RX470 series, and 2nd 470 via bridge won't add any performance gain
Person D -- Get the RX580.. it'll be best.

Lovely.

I would have gotten the RX580 w/8GB if it weren't for folks posting on here that it crashes in Vegas unless you stand on one leg and hop up and down chanting praises to Zeus.

So I purchased the system with a single RX470, 4 GB RAM in it because that's what it offered.

I must say -- I'm a bit disappointed with the voices of shared knowledge here on the forum. Conflicting information clouds guidance to those (read: me) seeking information on the basic question: "what will help Vegas 14 perform best for preview and for rendering to format A, B and C?"

Person A -- NVIDIA cards won't perform as well as AMD. Don't get NVIDIA
Person B -- Mix NVIDIA and AMD for best performance
Person C -- Don't get AMD RX580 or other series due to bugs. They won't work well with Vegas and will cause headaches. Only get RX470 series, and 2nd 470 via bridge won't add any performance gain
Person D -- Get the RX580.. it'll be best.

Lovely.

There is no confusion here aside from D; the poster may not know that there are issues reported with this card and Vegas.

You have to read every post carefully and yes, it requires understanding your workflow and needs.

A) is correct and there is no dispute and it doesn't conflict with B, C or D

B) Is correct for certain circumstances, read my post properly. It ONLY improves RENDRERING with MC AVC using CUDA; nothing else. Got it?

C) is also correct and is partially in line with D. The reason to get ONLY the RX470 is because a RX480 isn't offered.