I can tell you that I got X3:TC working in Linux on a netbook with an Intel Bay Trail processor (Bay Trail processors have probably some of the weakest integrated graphic cards of the entire Intel series of its time). The performance in crowded systems was let than stellar, but it was playable.

I'm surprised you're having issues. What exactly are you using in terms of hardware? I don't think Windows 10 will help much with VRAM usage to be honest. If you have an integrated graphics board it will just tap into your system RAM, according to how its driver/firmware tells it to do that.

Increasing the amount of system RAM will help, however, in most cases. Ideal is the case where you have a dual-channel compatible memory controller but only have one memory slot populated - if you buy a second one of the same capacity you'll activate the dual channel interface and get a bandwidth boost to your graphics card also. In most cases, the amount of memory allocated to the graphics card will also increase if you add more RAM.

I do not understand; it worked better than this before the switch to Windows 10 from Windows 7.

At home I have no problems but here I am using a laptop with: Core 2 Duo P8600 @2.4GHz & Radeon HD 3430M with 256MB onboard VRAM & 4GB DDR2 RAM in dual channel. 2 slots, both already occupied.

I will look into how Windows assigns extra video memory when needed from the normal RAM. The problem might lie there. Lowering the resolution a tad made the game much smoother but it is not good in a dogfight and the plots tend to put me into those like it or not.

Yes I know that graphics card is not really meant for gaming

Ok, that's a rather old laptop :).

When I first played X3:TC it was on a desktop with a noisy and radiator-hot Radeon HD 4650 and I remember it was having sporadic performance issues even on that and the GPU was hitting temperature highs of around 85C during gameplay.

Luckily those days are long gone and on modern hardware most integrated graphic chips have enough power to run X3:TC and X3:AP smoothly :).

Maybe upgrading to Windows 10 has put more strain on the already limited resources you had - you have to remember modern operating systems are not necessarily good for playing older games, especially on older laptops. I'd keep an older operating system installed if I were you - maybe revert to Win7 or try switching to Linux if you have the time, you might be pleasantly surprised in some cases. I don't think your problem is with the video memory to be honest, but the overall rendering power of the graphics chip, which is too low - but if that's somehow also affecting performance, you might want to lower the texture and shader settings a bit and see if it's any better.

Not my computer = not up to me what OS is on it. I did suggest trying Linux mint.... to no avail.

All settings on lowest was not enough so I bit the poisonous tasting bullet and lowered the resolution a bit.

My own laptop is unfortunately much older than this one so impossible to play on and my desktop is rather stationary, like those tend to be. Bringing it with me on the plane is not a realistic option.