SSD will make everything snappier - I highly recommend it.

But it may not improve your preview times that much unless your projects are quite large and don't fit in the disk cache.

A new GPU would only improve preview times if you have source clips in H.265 - which is not the case for your cameras.

Ultimately though, if your projects use a lot of effects, the only thing that's going to improve render times significantly would be a faster CPU, IMO. It looks like your 4770 / 3.4 GHz cannot be overclocked per http://www.tomshardware.com/answers/id-1829575/4770-overclocked.html

For that, best to start saving some money for a new machine with an 8, 12 or 16 core CPU when those become available in desktop versions .

I'm not that familiar with the Intel CPUs and sockets - maybe there is one you could swap in your existing motherboard for your 4770, but I'm not sure it would be worth it unless it's one of the 8 core/16 threads models. Check with HP and Intel for socket and CPU compatibility for your machine.
MSI X99A Raider
Intel i7-5820k @ 4.4 GHz
32GB DDR4 RAM
Gigabyte nVidia GTX 960 4GB
480 GB Patriot Ignite SSD (boot)
2 x 480 GB Sandisk Ultra II SSD (striped)
6 x 1 TB Samsung 860 SSD (striped)

2 x LG 32UD59-B 32" 4K
Asus PB238 23" HD (portrait)

Barry,

I agree, an SSD is one of the best upgrades you can get. It will help with the overall editing experience. A minimum 500 GB SSD would speed things up nicely and give you lots of space to work with. Save the final files to a regular mechanical HD backup and you are set. PD 14 Ultimate Suite / Win10 Pro x64
1. Gigabyte Brix PRO / i7-4770R Intel Iris Pro 5200 / 16 GB / 1 TB SSD
2. Lenovo X230T / 8GB / Intel HD4000 + ViDock 4 Plus & ASUS Nvidia 660 Ti / Link: https://www.youtube.com/watch?v=ZIZw3GPwKMo&feature=youtu.be

It seems the SSD is the way to go. Crucial has that nice scanner to look at the system and determine a compatible SSD, no one else seems to have that. Of course my biggest tech accomplishment is the install of a 4 port USB thingy and a Firewire doohicky in the back of my machine, so I am a bit skeptical of my ability to do this, but I've heard it ain't that bad. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
Nvidia GTX 960(4GB)/16GB DDR3/
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5.
Tape capture using 6 VCR, TBC-1000, Elite BVP4+, Sony D8 camcorder with TBC.
https://www.facebook.com/BarryAFTT

Quote: As it relates to performance in PD14, after looking at my dxdiag, and because of financial concerns, would I be better off with a new video card, or a solid state drive for Windows?

I cannot get both at this time, so I have to choose, but I'm really looking for a better real-time preview, render times are secondary to me.

I just upgraded to PD14 and have an i7-4790K, 16GB RAM, two SSD drives, and an old GT440 graphics card. When editing HD-MPEG2 video PD14 stops and studders at every transition unless I set the preview quality to "normal" (which looks terrible). Ironically, I never had this problem with PD13, but it doesn't appear to be related to processor speed, available memory, or the drives. I have a new GTX750 graphics card on order so I should know this next week whether that is going to have any effect. Anthony Watson
www.mountainsoftware.com
www.watsondiy.com

Hi Barry
The Upgrade Road is a Stony Road ....Electronic in 60 Days are " OLD "....I think graphics card ....If Possible only the Best for you !!!
God Luck Pauls PC
X399 AORUS Extreme/AMD Ryzen2970WX/1xQuatro 4000 Driver:Geforce 419.67Skill V DDR4 64GB/3200MHz/Win10 prox64
Intel SSD 750/400 / Intel SSD 750/1.2Tb 1x4TB SSHD /1xSeagate 10TB pro
1xSamsung UA28D590 4k LUMIX GH5 1xLG HDR

According to the HP website: http://support.hp.com/us-en/document/c03804605#AbT3 ,the Core i7-4770K(overclockable) was available over the standard i7-4770 for maybe $20 more. That is hindsight. Now it will cost about $236(new) now to replace it yourself. I agree with Julien Pierre on that one about the cpu overclocking being the best for your needs.

A GTX 960 video card is about $200 which allows you to do some hardware encode faster, no speed increase with svrt use which is what we suspect is possibly the way you use 1080/60i to produce or create those blu-ray. Browseing through the forums, we constantly see contributors telling members to turn off HA to fix the problems on their pc's. I don't know of any PD user having problems with the GTX 960 except maybe 1.

Your Drive C has 1866-1653=233GB of used space. That will fit in a 250GB ssd with very little room to spare. It will cost about $100 for a Samsung Evo 250GB or $170 for a 500GB ssd. Going back to your original post where other contributors advocated that you use a ssd: http://forum.cyberlink.com/forum/posts/list/50/43274.page .Others upgraded to a ssd and are very happy then. Since then I too upgraded my ssd to a 250GB samsung evo. Here is the crystal diskmark attached for it.

Your SATA III 6GB/sec. is better than some of those with older pc with SATA II and will get the full benefit. The prices quoted are those from microcenter. You can take your pick on what to upgrade. I would go along with the ssd.