i7 or more RAM??

If it was me I would first go for the cheaper option of buying more Ram and see how your system works. At the very least if you later  moved up to an i7 system, the extra money you spent on Ram for your old system would make the 2nd hand price more interesting to someone looking for an upgrade system of their own.
Hope it helps.

Dammit chuckebaby, you would have to say that!!! Ha ha!!! Since I've retired money is a little tighter than it used to be! I know you're right (you always are).
My current i5 does fine with all but the largest of my projects. Could bumping my RAM up from 8 gigs to 16 gigs give me any noticeable improvement in performance for the time being. If so, I could put off the larger expense of a new i7 system until I can better afford it.

rodreb
Dammit chuckebaby, you would have to say that!!! Ha ha!!! Since I've retired money is a little tighter than it used to be! I know you're right (you always are).
My current i5 does fine with all but the largest of my projects. Could bumping my RAM up from 8 gigs to 16 gigs give me any noticeable improvement in performance for the time being. If so, I could put off the larger expense of a new i7 system until I can better afford it.

Check the RAM usage in the performance monitor and/or Task Manager to see if you are anywhere near 8GB.
Unless you are running several instances of Kontakt or some other sample based synths, I doubt you will even notice doubling the RAM.
+1 to the I7-4790K. Still the best bang for the buck. I built a 4790 PC for my friend's studio this summer and it rocks.

If you're feeling the money crunch just buy some RAM, then start putting those pennies in the piggy bank for 6-12 months and buy today's latest and greatest for a couple hundred bucks cheaper.
 
But then if it's really stifling your creativity maybe it would be best to buy a new pc. 
 
Maybe you describe what exactly is not performing as desired and it could provide us with a little more insight. 

My desktop and my previous laptop both still had 8GB and were fine with that. I don't do orchestral stuff really but I do use plenty of Kontakt for piano, Rhodes and the odd string part or something more specific. They're both I7 though and I think the extra cores really make a difference, especially now with plugin load balancing. To be completely frank I would never even consider building a DAW with anything less than a quad core I7. Are there no I7s that fit in your mobo?

its a tough call Rod, I do know the place I deal with directly (Microcenter) have stores across the continental US.
they and a lot of other places that sell RAM (like New Egg, Exc) will allow you to return it if you find it "Defective" per say. some places wont even ask, just simply send it back and get your money back. Its hard to say with RAM, especially considering the each of us work individually in different ways. Some of us use a large amount of soft synths/sample library's, mixed with Audio tracks. while others use a ton of soft synths/sample library's which determines a large amount of how your RAM is being dispersed.
 
Back to my original suggestion, Order the RAM and give it a test run. if you don't like it, return it and get your money back. kind of a no loss situation. I've built several  DAW's in my time, both AMD and Intel and I have found Intel to be much more expensive and for years I battled with the assumption that the money was not justified for the extra price of an Intel. but after this latest build (I build back in April) I have a different opinion. I believe the extra money is well worth it for the Intel. they just seem to process everything so much faster.
 
I built a top of the line AMD build 3 years ago and it was fast. I had many debates with Jim Raseberry over the differences between AMD and Intel and I still stick by most of my theory's but he was right. Intel is far superior to AMD. though I will give AMD the upper hand when geared toward some of the gaming systems.
but were not playing World of Warcraft here
 
when your ready to upgrade (even if its in a few years) call me, I'll walk you through it.
we'll get a list together and build it from scratch. trust me I was in the same situation. I saved for almost 2 years putting change aside, extra money, sold one of my desks (Tascam M-50) and did it up good.

I do believe the difference between an i5 and i7 is the latter has hyper threading.  Also look for ways to reduce resources in your projects. I believe most developers these days care less about resource efficiency. 

kevinwal
The answer is of course to upgrade both. :)
I'm a big believer in more RAM is always a good decision. I like to have enough RAM in my system to completely eliminate the need for a page file. It's true that after a certain point more RAM doesn't speed things up, but it doesn't slow things down either. So if you're more able to purchase RAM now, I'd say get it. Once you have enough, then you can go for that CPU.

I agree with this in principle but I assume your current PC uses DDR3 RAM. The current I7's use DDR4 which is not compatible. If you update to the older I7-4790K (which is still a good chip) or a Broadwell family chip , you can use your DDR3. If you update to to Skylake or newer DDR3 will not work as DDR4 is the latest and greatest.
I would advise you to save your $$$ for a new CPU/PC. Have you looked at whether you motherboard will support a better CPU.
I had an E8400 CPU with 6GB of RAM and never had show-stopper issues with some fairly substantial projects.
Just get by for now with freezing synth tracks or tracks with monster FX chains if you have memory issues until you can afford to upgrade the CPU.

I think the I5 (at least the haswell one) benchmarks single core at 7000-ish and the 4790K at 11000-ish.
Most of that is due to the higher clock (4.0 Ghz). Throw in the hyperthreading and Sonar will exhibit really noticable improvement.
Both the I5 and 4790K use LGA1150 socket and both use DD3 RAM.
Rodreb may be able to simply swap the CPU in his PC then buy more DDR3 RAM when he can afford it.
Just make sure motherboard/bios supports 4790K (it should).

No go on the I7-4790K drop-in replacement.
Your I5 CPU is socket LGA 1155. I assumed you had a Haswell I5 (LGA 1150).
Best CPU for LGA-1155 socket is prob I7-3770K (Ivy Bridge) and a quick look shows it as kind of pricey (~$400). If you could find 3770K on Ebay or somewhere for $150 I would say OK but it is no where near worth $400 over the I5-2400.
See here
http://cpuboss.com/cpus/Intel-Core-i7-3770K-vs-Intel-Core-i5-2400.
 
If you have built PC's before I would say swap the motherboard, otherwise save up for a new PC.

I run a non K 3770 on my desktop and it's still a great CPU. I don't think the diff between the 37xx and 47xx was that huge and getting a "K" CPU is really only worth the extra dough if you're going to overclock which opens an entirely new can of worms. I haven't looked but I'm assuming the 3770 is more affordable, assuming it's still easily available.

Page file may be an issue. I recently increased the size of my page file. I do have it static, not dynamic. When I run Latency Mon, the page file is the only thing that is even close to being high. Can you run with no page file? I admit, I'm not real savvy on that.
OOPS! I meant page fault in Latency Mon!!

DrLumen
You can run without a windows paging file but windows doesn't like it and slows down without one. If you have an SSD, set the paging drive on your SSD at twice your current RAM for the min and max size. This makes what was once known as a RAM drive and helps a lot. The size is subjective but twice was once the common setting. Ultimately, setting the page file on a SSD separate from the OS drive is optimal.
 
If you don't have an SSD then try to put the paging file on a drive separate from the OS drive (different drive channels). Use the same settings as above.
 
Even locking the page file size down to the OS drive helps a little. FYI, locking down the page file size stops some disk fragmenting due to the changing page file size. Also, windows won't resize and possibly rewrite the page file at whim.

Good point,
if you don´t already run a ssd drve for your OS and DAW
this is the component that will give you the most benefit .

microapp
Check the RAM usage in the performance monitor and/or Task Manager to see if you are anywhere near 8GB.
Unless you are running several instances of Kontakt or some other sample based synths, I doubt you will even notice doubling the RAM.
+1 to the I7-4790K. Still the best bang for the buck. I built a 4790 PC for my friend's studio this summer and it rocks.

^^^This. More RAM will only help if it's a bottleneck now. Without using samplers, it's unlikely you're tapping out the 8 GB you already have, in which case adding more will do nothing for you. Sorry.
 
A faster CPU, OTOH, will allow more tracks and more effects before it runs out of steam, and video may be smoother. 
 
However, the same principle applies as with memory: there's no advantage to having more than you need. It's not a video game or a sports car. If your i5 has no problem keeping up now, and you don't plan on starting significantly larger projects, then you may be disappointed by a CPU upgrade as well. Windows will boot faster, SONAR will come up faster, but you won't notice any difference in your recording projects.
 
It comes down to whether or not your current system is ever NOT up to the task, e.g. you're having to freeze tracks to avoid glitchy audio, you avoid certain plugins because they cause dropouts, or you want to watch YouTube videos while you're recording (not recommended). 
 
Here's a thought: if you're looking for a cheap upgrade, consider adding a 1 TB external disk drive for backups. One you can disconnect and stash elsewhere in case your computer gets stolen.