Cooling and clocking

There are other relatively inexpensive options for extending the life of your existing desktop components too - overclocking your CPU can give you the extra bit of performance that might put off that expensive upgrade.

Dropping less than £50 on a closed-loop liquid CPU cooler will give you the thermal headroom you need to indulge in a spot of the ol' chip-cooking. That should give you a performance boost without you spending a huge amount of cash.

The outside counts too

You don't need to simply spend cash on your internal components either. If you've already got a decent GPU, an SSD, a good chunk of RAM and a reasonable HD monitor then you're not going to be gaining anything dropping £100 on your internals.

There are still some effective upgrades that won't require you to wield a screwdriver. A good quality keyboard can be a joy to use. Whether you just use your machine for gaming or you like to indulge in a little light wordplay on the side, a decent keyboard is a worthy investment. I'm a big fan of mechanical switch keyboards, but they are on the pricey side. You can, however, pick them up for less than the £100 mark we've set ourselves in this upgrade session. Personally, I think Gigabyte's latest is one of the finest keyboard I've ever used, and while £100 for a board is a lot of cash, it's something that will probably outlast most of the other upgrade options in this feature.

The keyboard and mouse combo is the hallmark of PC gaming, and spending a decent amount of cash on a quality mouse will deliver its own rewards. I was happy gaming with an old Microsoft Intellimouse for years, but as soon as I laid my twisted claw on a Logitech G9, I was hooked on weighty, accurate gaming mice.

You don't need to go all the way up to £100 for a rodent that will enhance your experience. We've split up the categories over the page, offering our pick of the best £100 or so upgrades for each. What we can't do, however, is tell you which is necessarily right for you and your rig.

The beauty of the PC is that no matter what system you've got now, there is probably an upgrade out there that will improve your system for under a ton.

Graphics card

Pint-sized pixel-pushers for less than a ton

HD 7770

For any PC gamer, the graphics card is probably the first thing that comes to mind when you're thinking about upgrading your machine. We've hit the end of this last generation of graphics cards, and with the new AMD and Nvidia GPUs coming sometime around the tail-end of this year, prices are about as low as they're likely to get.

That said, we could see new silicon filling the gaps in this generation, like the HD 7870XT, but that may still not drive prices down. This generation has seen AMD become a far more aggressive competitor over price than it has in the past, and that means us consumers get far more graphical grunt for our money going for a Radeon card over an equivalently priced GeForce card.

The example in the sub-£100 market is the HD 7770 going up against the GTX 650. That's a complete mismatch in terms of gaming performance, with the Radeon card posting significantly better results in the latest games than the Nvidia GPU. At 1080p resolutions and the graphics settings on full there's at least a 10fps difference between the two GPUs in most titles. Batman: Arkham City is the exception, but in other Nvidia and AMD-sponsored titles, the gap is at least as wide.