Create partition to upgrade OS 10.6.8 to 10.8.5?

Question

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Model Name: Mac Pro
Model Identifier: MacPro3,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.8 GHz
Number Of Processors: 2
Total Number Of Cores: 8
L2 Cache (per processor): 12 MB
RAM Memory: 18 GB
Graphics card: ATI Radeon HD 2600 XT:
Backup using Time Machine Backups on a 1 TB Fantom WD10EAVS-00D7B1 drive
Available Mac HD disk space: 58.01 GB
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I need to upgrade my early 2008 Mac Pro3,1 from OS 10.6.8 to 10.8.5 in order to download Autodesk Maya 2015 for a 3D animation class.
10.6.8 has served me well, supporting my use of Adobe CS5 Production Premium applications; Adobe CS4 inDesign; Audacity Sound Editor; and other programs for web, graphic design and video editing.
But my major concern in upgrading to 10.8.5 is that my existing application software I use for 2-D stuff will continue to work.
Here are my questions:
1. If I create a partition on my Mac HD and install 10.8.5 on that partition it as my startup disk, will this be my escape clause if some applications do not work with 10.8.5? (i.e. Can I revert to the unpartitioned part of the HD to start up with 10.6.8?)
2. How large should a partition used for 10.8.5 be?
3. Should I download and install Maya 2015 to that partition as well?
4. Is my Time Machine Backups external drive sufficient to qualify as backing up my HD? If so, should I power it off before doing all this?
Any answers to these questions or or further advice on this would be greatly appreciated. Thanks in advance.

Answer 1

Easier to show you products I think
This adapter:
Lycom DT-120 M.2 PCIe to PCIe 3.0 x4 Adapter (Support M.2 PCIe 2280, 2260, 2242)
Then the "blade" is an SSD that fits on a PCIe adapter so it is different than your 2.5" SSD.
These were first used in MacBook Pro 2013, they are "blade" shape and is what is found in the Late 6,1 2013 Mac Pro black cylinder.
Minimum is fine for most, but not if you use Adobe or heavy graphics or video, then larger is better. And larger also means faster. They are plug and play, no support needed, support is built into the Mac Pro already all models from 2006 thru 2012.
This is what I would recommend. Costs 2x as much but no $100-300 controller needed, no issues with booting that many other cards exhibit.
Samsung XP941 256GB PCIe 2.0 x4 M.2 SSD MZHPU256HCGL
There is smaller 128GB for $142 (Amazon) or $136 (Newegg, sh extra).
Took me multiple reads of this growing thread to finally take the plunge myself - no regrets.
http://forums.macrumors.com/showthread.php?t=1685821
Good spot in middle of thread:
http://forums.macrumors.com/showthread.php?t=1685821&page=9
I would need two SSDs, maybe even two controllers, to get 900MB/sec writes and 1100MB/sec reads.
That is 10x better than hdd which have slower seeks (8-12ms) and access, whereas SSD in blade form is as close to zero as it gets.
As for graphics card, 4GB GTX 770 would be a good option.
http://www.macvidcards.com/store/p9/Nvidia_GTX_770_2_GB_and_4_GB.html
macvidcards
Latest test results (770 is not but the 780 is) and the GTX 970 or 980 look promising
BAREFEATS
GeForce GTX 980 vs 9 other GPUs running Resolve, LuxMark, and Octane Render
INSIGHTS
The NVIDIA GeForce GTX 980 beats all other GPUs rendering noise reduction in DaVinci Resolve.
As for OpenCL in LuxMark, one GPU edged out the GTX 980: the AMD Radeon R9 290X. The GTX 980 still impresses since it is twice as fast running LuxMark than the next fastest NVIDIA GPU, the GTX 780.
Only NVIDIA GPUs appeared in the Octane Render graph. That's because only CUDA capable GPUs are compatible of rendering in that app. The GTX 980 edges out the GTX 780 and blows away all the other NVIDIA GPUs. Notice we included results for dual 980s. That's a teaser for an upcoming article.
We wanted to include a graph showing After Effects CC 2014 rendering the Robot ray-trace 3D project, but AE gives us ray-trace loading errors when we attempt it with the GTX 980. Once that issue is resolved, we will add that graph to this page.
The GeForce GTX 980 may not have dominated every test but keep in mind that it ran with only the Mac Pro tower's internal power no matter how hard it was stressed. That can't be said of the GeForce GTX 780, Radeon R9 290X, and Radeon HD 7970 -- all of which had one power port plugged into an auxillary power supply to prevent possible self-power-down by the Mac Pro.
http://barefeats.com/gtx980b.html
Bear in mind, these would bring your system up as far as feasible or possible and only other item would be a couple 2-4TB HGST drives. The system boot drive can be small and fast, and should not have any media, data or such - unless you have a large enough SSD blade, then having those with its ultra-high I/O is fine, so Lightroom, scratch and such benefit. But media projects, most video projects, no . There are a few hardy souls that are building out 2TB of SSD for large volumes for their projects and work (4 x 500GB and above).
When I put a SSD in my system in 2010 it was nice. When I upgraded in 2013 it was better. The last year though has seen a lot of improvements. And reductions in price. So that today any Mac can come with flash storage - great for its no noise, almost no heat, and tiny size. 80 x 22mm is small! Took me 4 minutes to attach to the Lycom adapter. Instantly recognized, formatted, and cloned the system to SSD using Carbon Copy Cloner. Boots instant, and system response for loading apps, data, graphics, AND writing to disk are nearly instantaneous.