Is the golden era of laptop gaming a goner? Let's consider the past a second. Wind the clock way back to September 2005 and Nvidia had just launched the GeForce 7800 GTX Go. It was a big, bad 24-pipe beast.
What's more, the mobile and desktop iterations were absolutely identical, save for a small gap in clockspeeds. Finally, mobile machines could go toe to toe with their desk-bound buddies.
Sadly, it was but a temporary anomaly. Nvidia did manage a follow up with the closely related 7900 series but since then, there hasn't been a pukka mobile graphics chip hewn from precisely the same silicon as the very fastest desktop GPU of the day.
Ultimately, there's no getting round the constrained thermals, packaging and power capacity of a portable, even one with pizzabox proportions. That's especially true now that graphics chips are massively parallel monsters with hundreds of fl oating point processing units.
The grunt gap
The bottom line is, you're not going to be able to achieve true desktop performance with any machine that can truly be described as portable. Graphics performance is critical for gaming grunt and without access to the fastest video chips, laptops are always going to be second string.
But that doesn't mean gaming on the move is futile. Lordy, no. The best mobile graphics chips may not be as quick as the very finest desktop fare. But by any sane metric, they are incredibly complex bits of kit, capable of astonishing feats of 3D rendering.
The fact that PC graphics in terms of game engines has somewhat stagnated helps, too. Partly that's because prevailing games consoles tend to set a fixed target for cross-platform developers and current consoles are getting on a bit. More to the point, there are mobile graphics chips that thump seven shades out of any console. But exclusive-for-PC titles haven't exactly raced ahead, either.
Meanwhile, the old will-it-play-Crysis adage seems more irrelevant than ever. All of which means you can have your portability pie and eat your gaming gateau.
Take laptop gaming, simmer over a low heat and reduce to its core components. You'll be left with three things. Graphics, graphics and graphics. Okay, it is possible to spoil a mobile gaming rig by plopping in the wrong CPU or slapping on a shonky screen. But without a shadow of a doubt, the most critical single component is the graphics.
That may seem obvious. But there are shed loads of serious sexy looking multimedia laptops out there. It would be awfully tempting to gloss over the mediocre graphics in return for a shiny screen and a slick looking chassis. But trust us on this. That would be a monumental mistake.
The first rule of mobile gaming, then, involves discrete graphics. Put simply, you need a separate video chip. No ifs. No buts. Do not pass go. Do not collect £200. Just ensure any laptop you buy with a view to gaming has a discrete GPU.
Integrated graphics
Admittedly, both Intel and AMD offer much better integrated graphics today than ever before. AMD in particular has upped its integrated game with the Llano APU, which packs no fewer than 400 stream shaders, making it massively more powerful than the 80 shaders of its past best.
The problem is, even with 400 shaders Llano's performance is only on a par with a fairly lowly discrete graphics card. More importantly, the in-game experience with the latest and most demanding titles is miserable.
This isn't going to change any time soon and a big part of the reason why involves memory bandwidth. Good GPUs have superwide memory buses of 256-bit or more. They also pack crazy-fast GDDR memory with effective data rates north of 5GHz. Put the two together and you have a recipe for bandwidth bigness measured in hundreds of gigabytes per second.
And before you ask, yes, even mobile graphics cards have pretty quick memory chips. The current state of the mobile graphics memory art is good for around 100GB/s of bandwidth. Now consider a modern CPU with on-board, integrated graphics. AMD and Intel's mainstream processors have memory controllers with just two 64-bit channels. Even Intel's LGA 1366 beasties only have three 64-bit channels. Meanwhile, you'll be lucky to hit 2GHz data rates for main system memory.
All in, an overall bandwidth result measuring 20-something-GB per second is a great result for a CPU. In other words, discrete graphics chips have orders of magnitude more memory bandwidth. And don't forget, what little bandwidth is available for the CPU must be shared with the integrated graphics core.
At low resolutions and detail settings or paying ancient games, the impact isn't too awful. But who wants to play old or ugly games? It almost doesn't matter how powerful AMD and Intel make their next generation integrated graphics cores. It's actually the memory interface they need to sort out first.
Unless you're happy restricting yourself to five-year-old titles or jaggy pixel vision in newer games, then, the advice regarding integrated graphics remains the same. No touchy. So, now that you're convinced your gaming portable needs a proper graphics chip, the big question is which one.
As it has been, is, and seemingly shall ever more be, it's the AMD-Nvidia duopoly that owns performance laptop graphics. A quick browse of their product lists will throw up a lot of very familiar looking brands, monikers and product numbers. Simply a stick an 'M' for mobile on the end of any given desktop graphics chipset and you have its laptop equivalent.
Processing power
Sadly, however, all is not quite what it seems. For instance, Nvidia GeForce GTX 580M is not a 512 stream processor powerhouse like the GTX 580 desktop chip. Instead, it packs 384 processors.
The same goes for AMD's top Radeon HD 6990M. Not only does it not pack dual GPUs like the desktop 6990M, but the single GPU it does have is from a rung down in AMD's GPU hierarchy. If that sounds confusing it's because it is.
But once you get over the disappointment of the misleading product names, there is some consistency. For starters, both AMD and Nvidia are up to exactly the same game. And as a general rule of thumb, and just like the examples above, mobile graphics chips are based on the GPU one below the desktop chipset of the same name.
From the very top and kicking off with Nvidia, then, we get the aforementioned GeForce GTX 580M and its 384 stream processors, 64 texture units, 32 ROPs and 256-bit memory bus. Clearly, what we have here is the GPU known internally at Nvidia as the GF114 and sold in desktop trim as the GeForce GTX 560Ti.
While it may not be Nvidia's top graphics chip, it still weighs in with a barely believable two billion transistors, making it massively more complex than the likes of a £800 six-core Intel CPU. As for clock speeds, the mobile GF114 loses around 25 per cent compared to its desktop sibling. The same goes for memory data rates.
Next up is the GTX 570M. Once again it's based on GF114 but with a few sectors disabled. The result is 336 processors, 56 textures, 24 ROPs and a 192-bit memory bus. Then there's the GTX 560M. As per the one-rung-down rule, this little beauty uses the chip formerly known as GF106. It's the GPU that powers the GeForce GTX 550 Ti on the desktop. Vital stats include 192 processors, 32 textures, 24 ROPs and a choice of 128-bit and 192-bit memory buses.
Below that, Nvidia does have further discrete mobile graphics offerings. The GTX 555M is essentially a slightly hobbled 560M and worth a look if the price is right and you're on a tight budget. But we wouldn't go any lower than that. The 550M, for example, makes do with just 96 processors and under 30GB per second of memory bandwidth. We really wouldn't go there.
As for AMD, the Radeon HD 6990M takes pole position with 1,120 stream processors, 56 textures, 32 ROPs and a 256-bit memory bus. It is, in other words, none other than Barts, the chip found in the Radeon HD 6870 desktop GPU family. Remember, however, that AMD and Nvidia's stream processors are far from equal. Despite what appears to be a massive advantage over the GTX 580M, the 6990M delivers very similar performance.
Drop a rung and you come to a pair of cut-down Barts GPUs with 960 processors, 48 textures and 32 ROPs each. The only difference between the HD 6790M and HD 6970M is a 100MHz core clockspeed advantage for the former.
Rounding out AMD's interesting mobile graphics line up are a trio of laptop chips based on the Juniper GPU: the HD 6870M, 6850M and 6830M. All sport 800 processors, 40 textures, 16 ROPs and a 128-bit memory bus. Again, it's the clockspeeds that set them apart. What's more, just like Nvidia, AMD does offer a number of more modest mobile GPUs. And once again, we wouldn't go there.
Pixel punch
Matching screen resolution with GPU power is another crucial ingredient for mobile gaming. More pixels make for sharper, more dramatic visuals and, just maybe, more immersive gaming. But they also ratchet up the workload.
It's also worth remembering that even a monster 17-inch lappy has a much smaller screen than a modern desktop PC. And that means you don't need full-HD resolutions to have a nice tight pixel pitch.
Of course, you're probably going to be using your get-up-and-go gaming rig for more than merely fragging. So you don't want to go too low. Unless you're on a seriously stingy budget, we'd therefore avoid 1,280 x 720 or 1,366 x 768. On the other hand, 1,920 x 1,080 is really too much for all but the most powerful mobile GPUs. In fact, if you want the best possible longevity of gaming grunt, we'd probably recommend you avoid 1,080p, period.
Instead, 1,600 x 900 is probably the best all round compromise between graphics workload, eye candy and desktop elbow room. Shame, then, that it's one of the more rarely offered resolutions.
While we're on the subject of screens, it's sad to have to report that laptop LCD technology hasn't been doing anything interesting lately. A couple of years ago, the switch was made from 16:10 to the slightly wider and more HDTV-friendly 16:9 format. The same thing happened on the desktop at around the same time.
For the most part, we'd prefer laptops had stuck with the slightly taller 16:10 standard. A PC is not an HDTV and whether you're on the desktop or in-game, the vertical pixels you lose with 16:9 are sorely missed.
Panel technology
Elsewhere, screen technology has stayed more or less static. The vast, vast, vast majority of laptops make do with TN panel technology. And not terribly good TN technology. If TN desktop monitors have mediocre contrast, colours and viewing angles, mobile TN screens are usually significantly worse.
However, since we're talking about gaming lappies, TN does at least offer good pixel response. Mobile IPS screens, by comparison, usually offer serious sluggish response times. The one exception to this litany of same-old screen technology is the wide adoption of LED backlighting.
Problem is, almost all laptops have cheap white LEDs rather than pukka RGB LEDs, so the benefit in terms of colour depth is slim to none. However, LEDs are more power efficient than boggo CCFL LCD backlights, which is obviously handy for any portable PC. They also tend to last longer before losing brightness, which is nice.
Now, we mentioned earlier that gaming laptops are all about graphics. However, you do need to take a little care with your choice of CPU. As things stand, we're not too keen on AMD's notebook processors. The Athlon II and Turion II mobile processor cores we'd say forget about, they're just not up to snuff for gaming. And as we've already established, anything based on the Llano APU isn't going to be fully fit for gaming purpose.
Bulldozing ahead
The Phenom II dual, triple and quad-core mobile processors are more interesting. But they're also pretty rare. If you can find one that perfectly suits your needs, they're worth a look.
But we certainly wouldn't compromise on other specifications in order to secure a Phenom II. All things AMD are subject to change when Bulldozer-based chips arrive, of course. In the meantime, your best bet is one of Intel's Core i3, i5 or i7 processors.
Clock-for-clock, Intel's processor cores have been gruntier than AMD's for several years now. That's a critical issue in the context of mobile machines running at lower frequencies.
Best gaming laptop: the contenders
Acer Aspire Ethos 8951G - £1499
Alienware M14x - £1779
Medion Erazer X6811 - £799
MSI GT780DX - £1497
Rock Xtreme 786 - £1799
Rock Xtreme 685 - £1649
Sony VPC-F21Z1E/B1 - £1589
Toshiba Qosmio X770-107 - £1499
you will see in the video, the J3500 portable convertible keyboard is so well balanced and comfortable that it is even easier to use than a standard laptop keyboard. 
keyboard option attaches to the back of the unit for carrying 
