Dual 30" ACD setup - two 5770 or one 5870?

[dubsac]

My current machine is a 2007 17" MBP 2.4Ghz that I run in lid-closed mode at the office with a 30" ACD for display. I run an eCommerce business and am looking at upgrading to a new Mac Pro and dual 30" setup for more screen real estate.

I am not sure whether it would be better to start with one 5870 or two 5770 video cards to run the dual 30" monitors. Both options are about the same cost ($200 vs $250) and can power both displays. From what I have read on this forum about the 5870, it seems to offer better gaming/3D rendering performance. Some have suggested that two cards are better for multiple monitors, but I am fairly sure that they were referring to a 3+ monitor setup. I doubt I will ever need more than two 30" monitors, but you never know. If I went with one 5870, could I add a second in the future? I don't do as much gaming as I used to (too busy) but I might get back into it casually some day.

The setup I am contemplating is a 3.3Ghz 6-core or 3.2Ghz 4-core with base RAM and HDD, then upgrading to 10 or 12GB RAM and a SSD boot disk. Any suggestions are appreciated. Thanks!

 

[bpd115]

If you run both displays from one card it halves the VRam per display which effects gaming performance.

 

[Hellhammer]

If you're running GPU intensive tasks on both monitors, then dual ATI 5770 should be faster as both screens would get 1GB of VRAM. If you're using one as a main screen and second one as secondary, then it might be better to get ATI 5870 as then all of its power can be dedicated to the one monitor when needed.

IIRC 5770 is half the speed of 5870 (1/2 of the STREAM cores, 800 vs 1600) so dual 5770 would be theoretically as fast (or faster due to extra VRAM). I'm not sure can you use the second ATI 5770 for rendering, that would make them pretty equal.

 

[bluesteel]

how about if you have two 27" Cinema Displays, and your running a program like Maya 2011, where the viewports rely heavily on a graphics cards memory for performance....would a person be better off with one 5870 or two 5770's? or one 5870 and one 5770 (if thats even possible)?

 

[bpd115]

how about if you have two 27" Cinema Displays, and your running a program like Maya 2011, where the viewports rely heavily on a graphics cards memory for performance....would a person be better off with one 5870 or two 5770's? or one 5870 and one 5770 (if thats even possible)?

I can't really answer most of your questions, but you can mix graphics cards. I'm running a Radeon 4870 which drives my 30" ACD and the original GeForce 7300 which Runs a 23" ACD and a 17" LCD.

 

[sepu]

Def 5870 will be better for Maya or any 3D app ... I use Maya, Zbrush (Mudbox) will performance a lot better

 

[spaz8]

I've been contenplating this very thing.

I do 3d work. I think the caveat for you is that I don't think the MP Power supply can power a 5870 and a 5770. I think 2 x 5770 just squeeks in under 300 W.

I thought I read somewhere that the 2nd card becomes a frame buffer, maybe this only applies to the PC if you are not in a crossfire setup.

Since I can't seem to get the 5870 without buying a new machine, it looks like my choice is made for me to get 2x5770's.

 

[bluesteel]

I do 3d work. I think the caveat for you is that I don't think the MP Power supply can power a 5870 and a 5770. I think 2 x 5770 just squeeks in under 300 W.

I thought I read somewhere that the 2nd card becomes a frame buffer, maybe this only applies to the PC if you are not in a crossfire setup.

Since I can't seem to get the 5870 without buying a new machine, it looks like my choice is made for me to get 2x5770's.

can you explain more about what a frame buffer is, and how that might apply to an application like Maya 2011?

just so you know, the new nVidia Quadro FX 4000 for Mac appeared in the Apple Store for a short time at $1199 with the shipping date "unavailable", but now its gone. i'm considering the purchase of it once its available on Amazon or something, where it will probably be at least $100 cheaper. if i get one, i'm going to sell the 5870 in my new mac pro.

 

[spaz8]

can you explain more about what a frame buffer is..

Well the way it was explained to me is that basically one card is handling the screen redraw, and the 2nd card is just a reservoir of ram, so u would have 2 gigs of Vram in this case. I don't think this applies though.. because I assume you would hook up one monitor to each card, meaning each card is responsible for rendering 1 monitor.

As I think about it more, I think this only happens in windows, when you have two cards, but that are not crossfire.

 

[bluesteel]

I think this only happens in windows.

i think you might be right about that.

 

[jav6454]

Any suggestions are appreciated. Thanks!

One HD5870 for main + secondary. Two HD5770 dedicated per monitor.

IIRC 5770 is half the speed of 5870 (1/2 of the STREAM cores, 800 vs 1600) so dual 5770 would be theoretically as fast (or faster due to extra VRAM). I'm not sure can you use the second ATI 5770 for rendering, that would make them pretty equal.

This is half true. The actual real performance of a 2x Crossfire of HD5770 yields the same level of performance of a HD5850. Reason for this has to do with not so perfect scalability of the GPUs.

 

[ycookmd]

I would recommend 2x 5770 cards. I recently purchased a 6-core 3.33 MP and my only regret so far is getting the 5870 instead of 2x 5770s. I am having occasional sleep issues with my 2 NEC monitors using the MP's MDP ports and MDP-DP cables from Circuit Assembly. They are minor but annoying, and I wonder if the issues could be solved by using MDP ports on separate 5770 cards, rather than the 2 on the same card.

To address your specific question, however:

Unless the ACDs have changed, the 30" ACD utilizes a dual-link DVI connector... so if you are using 2x 30" ACDs with the 5870 (which has only 1 DL-DVI port) you will have to connect the second 30" ACD using the Apple Mini-Display Port to DL-DVI adapter. Not only does this adapter cost $100, it is a very poor product.

I purchased that adapter to connect my 30" ACD to a new Mac Mini I purchased a few months ago. It continues to have the "black screen flicker" and occasional start issues -- despite the most recent firmware upgrade. Read the reviews on the Apple site for details. Although I have 2 new NEC PA-271 monitors for the new MP, out of curiosity I hooked up the 30" ACD to the MP with the adapter to see if the flicker/start issues persisted (wondering if maybe it was just the video card in the Mini). No -- the issues persisted, even with the 5870 in the MP.

I do not recommend the Apple MDP to DL-DVI adapter for any use. It is a poor product and the most recent firmware has not fixed the issue.

 

[cutterman]

To answer the OP's question, I am using 2 30" ACD's with a single 5770 card and the dual link DVI adapter. This config works fine for me and I have had no video problems (knocks on wood). I use it for amateur photo and video editing. If you are still interested in gaming the 5870 may be the better choice.