Your T5600 Precision in itself is OK, but the CPU and RAM that you have are WAY sub-standard for running Premiere smoothly.
I have a "render power" spreadsheet that is a simple calculation of:
Number of cores
1 (if no Hyperthreading) or 2 (if Intel CPU support Hyperthreads)
base clock frequency
So here are just a few of the results for Xeon e5-26xx cpus:
e5-2609 = 9.6
dual e5-2609 = 19.2
e5-2687w = 49.6 - top workstation CPU, VERY fast
dual e5-2687w = 99.2
e5-2670 = 41.6
dual e5-2670 = 83.2
If you're not opposed to buying on eBay, you can get used e5-2670 CPUs for just under $150/each. They had originally sold for about $1600 each. I still have a dual e5-2687w Dell T7600 and it is very capable, but those CPUs even used would cost you a good bit more.
So, upgrade to dual e5-2670 CPUs!
You definitely need more RAM too. That should not be too expensive to upgrade to at least 32GB.
...asssuming you take Jim's advice to improve the CPU and memory situations, you may want to double check your storage situation as well, to insure you have no "bottlenecks' there.
Generally, the contents of your "boot drive" should be limited to Operating system, programs, and Windows page file only. Being that SSDs have come down so much in price, it is well worth using a 500GB Samsung 850 Pro as the boot drive compared to the slow, spinning hard drive. Your system will be MUCH "snappier". 256GB will be just fine, but, 500 GB and higher are more reliable.
Secondly,you mentioned two other HDDs that were in a "RAID", but, you did not specify which TYPE of RAID. If it is RAID 0 you would be getting faster performance than a single drive,but, risk losing ALL the data on that volume if either one of those drives fails.
In addition, it appears you may be placing your media footage and project files on your boot drive.....a BIG NO - NO !! This is because you said the RAID was for "captures and previews" If you ARE doing so, this in itself can cause poor performance.
One quality SATA III SSD will far outperform a 2 HDD RAID 0, if that is what you have. Two SSDs in a RAID 0 would be even better.
The Crucial MX 200 series SSDs are very close in performance to the top rated Samsungs 850 Pros and are even more reliable, even though they are much cheaper.
Go to PPBM7.com website to test your current machine using the Premiere Pro benchmark test. This will identify any problem areas in your system.
It is important that your video footage is on the fastest volume you have in order to get good performance. If you have NO budget to improve your storage, at LEAST make sure all your hard drives are defragmented and not more than 50% full. Then, make sure "indexing" is turned off on all your drives. Make sure that you DO have a "RAID 0" on those 2 remaining HDDs and test its speed using a free utility like ATTO.
Place ALL files other than what is on the boot drive on this RAID 0 array for best performance. However, it would be EXTREMELY important to backup that RAID constantly to avoid losing all ts data. You would have to purchase ANOTHER large HDD for that!.
It would just be better to get at least two, maybe three SSDs and use the spinners for backing up and archiving.
Just circling back to say a major thanks for helping me with this performance issue.
Long story short I took your advice Jim and upgraded my machine with the dual e5-2670 CPUs, changed my C: drive to SSD and threw in some extra ram and my machine FLIES in comparison to the previous specs. I have zero problems now and am able to use my full arsenal of Lumetri and effects.
thanks so much for your help!