I have been having issues with FSX freezing using Carenado aircraft, REX Essentials + Overdrive and MyTraffic 2013.  I finally let it sit there frozen for a minute or so and finally got an error message saying I was out of memory (8GB of RAM) and to lower my settings, I dumbed it down one notch (from maxed out / ultra high to high) and it's been doing somewhat alright, but several times it crashes and says 'a fatal error has occurred' and reboots FSX.  I just ordered another 16GB of RAM (system is expandable up to 32GB, 4 slots for 8GB cards), this will give me 24GB of RAM.  My system was just released by HP last year, could it be too that I need a more powerful video card? Current stock video card is Radeon 7560D - 4059MB

Sorry if it offends, but it sounds as if you’re throwing money at a problem that you don't understand.

First off - HAVE YOU MADE A BACKUP? Do that before anything else. There IS a reason that you need to do this first.

If you have Windows, have you made a "System Repair Disk"?

Next - download a free program that shows what is going on in your computer. YES. I know that you can press CTL/ALT/DEL. But some viruses will pause their activity if you do that. What you want to look for is how active your CPUs are. Are they all hitting 100%? How much activity is going through your network card? Also check your hard disk activity. A lot of reads and writes? If so, you'll have to read up on it yourself. Too long to go into here.

If you think that you might have a virus, MAKE A BACKUP. Even if your backup now has a copy of the virus you still have a backup. I had a virus move the MBR (Master Boot Record) to a new location, AND it encrypted the hard drive. After I removed the virus I could no longer start my computer and no data was recoverable.

In so far as the computer crashing you could be having a component failure: hard drive, motherboard, memory, even the video card could make your system crash. No matter how new your system is, you can still have something go bad after a bit of use. Is the fan on the CPU running? What IS the CPU temperature?

Unless you're editing movies, your memory is more than you need. But as you have so much, you have 2 ways of testing it. The best is to download one of the many free memory testers. If you find one that doesn't require you to restart you computer to test it, then skip that one and find another one. Generally your looking for one that will autoboot from a CD BEFORE your operating system, so you may need to change your BIOS. The other way to check your memory? Just swap it out, one at a time. Not the best way, but it often works.

The question "could it be too that I need a more powerful video card?" is what makes me think that you're just throwing money in the vain hope of fixing the problem. I have a Radion HD 6870 (a much slower card compared to yours) with only 1GB of DDR5, and I usually run 5 to 6 monitors with most of the settings in FSX near the max settings.

In a nut shell - your problem probably isn't in the flight sim. That's just where you're noticing it.

I'd say look into a Better Graphics Card, and a better faster processor.

Now with that being said,,, IF you do go get a better Graphics card, YOU need to definetly look at the POWER SUPPLY Required to operate that New Video Card / Graphics card !!

I upgraded my Graphics card, and I also found out that the current POWER SUPPLY I had was NOT going to power the New XFX series Video card ! ( Very Very Important) !! 
 
So definely READ the side of the Box of the newer Graphics card,, before you buy it,, so you'll know before hand,, IF you also need to upgrade your main power supply !!

I ended up with a 650 Watt Power Supply, the requirements for the New XFX Video card that I got, was 600 Watts.

I operate / run FSX Gold / Acceleration on High settings

NO REX
only a few enhancents, 
Freeware Orbx grass scenery
FS Scene Global Scenery
few ORBX Scenerys
PAYWARE Scenery from Pac Sim / Pacific Island Scenerys
and over 4,000 Aircraft in my FSX Simulator to date.

what I see happening is a lotta people trying to JAM a whole bunch of supposed programs / products into the sim / computer, because it says its for this sim or that sim,, so it must be OK ???

Ya, but it doesn't all work together and jive, like its supposed to,, either, especially with low or medicore computers especially.

Bout' like taking Coffee & MILK and dumping down your Engine,, its Liquid right, so it'll go in, just like oil,, and everything be just hunky-Dory - right ,, cause its Liquid  ;D ;D  ::) ::)  :-? :-?   

Remember this - KISS ( Keep it Simple Stupid) you'll be way btter off in the long run !

I'd rather be Flying enjoying the Fine Aircraft out there and scenery - NOT constantly Tinkering with programs and the computer trying to Fix things , thats the case, so much for the actual joy of the flying simulator - you've now become a Virtual Fix it Technician , instead of a Virtual Sim Pilot, like so many intended to be !!

Video card, Power Supply and better processor - you'll be set - I'd say !

But what do I know,,  ::) - I'm just sum ol' Sim Pilot with 4000 Aircraft in my Sim,, ::)  :-?  ;D !

Dats, my 2-cents worth ,  ;)  ::)

Jet

You should be running FSX very good!
That being said, the question could be, how much programs/startup/processes you have running along with FSX, ref your memory problems.

You could try
http://game-booster.en.softonic.com/
Just to see if it helps.
Good luck.