Memory group tests like this tend to get all hung up on speed, but of course there’s another major issue when it comes to buying RAM. How much of the stuff do you need? Six gigs has become the de facto sweet spot for high-end gaming machines, but with so few games and applications being 64-bit, does stretching about the 32-bit OS cap of 3-and-a-bit gig really achieve anything? Hence, we’re pitching Crucial’s affordable 3GB DDR-1600 kit against Trident’s pricier, fancier 6GB DDR3-2000 kit.

Reflective of the massive variance to be found in the confusing DDR3 market, this is an unusual pairing – the Crucial sticks offering faster latency than their otherwise better-specced rival here. The Tridents also sport a fancy-pants heatspreader/sink, while the Ballistix go for just subtle side-panels. That 2 000MHz speed rating on the Tridents is a funny bugger too, as bus and QPI limitations on many Core i7 motherboards mean your plum won’t get up that high, unless you’ve got one of the crazily expensive high-end i7s, with their precious unlocked uncores.

Uncore and More

Ah – we’re throwing confusing terms about willy-nilly. Let’s get a couple explained before it gets out of hand. The ‘uncore’ is Intel’s made up name for pretty much everything in a Core i7 that isn’t a core – most notably the cache and memory controller. Because the memory controller is onboard the CPU isn’t handled by the motherboard for i7s; to raise memory clockspeed you have to raise this so-called uncore. Unfortunately, bar a few forgiving motherboards, this can’t be done on the i7 920 and 940 – only the 965 Extreme Edition. This means that, if you want to overclock memory, you’ll have to overclock the host bus -and thus the processor itself as well.

Conversely, if you want to push the bus sky-high to achieve epic processor gains, you need memory with room for all that growth. So, 1600+MHz DDR3’s main use is to increase the amount of overclocking headroom available, if you want to go for really big clock speeds from an i7. If you simply run it out of the box at standard BIOS settings, it’ll stick to 1066MHz and thus have literally no advantage over boggo DDR3-1066. In other words, if you don’t want to push your i7 far out of its comfort zone, neither of these kits are worth upgrading to if you already have some triple channel DDR3.

The QPI, meanwhile, is Intel’s QuickPath Interconnect, its rival to AMD’s long-running Hypertransport. It dictates the maximum available memory bandwidth, and to take this higher you’ll need to feed it more volts. On that subject, both these kits require that the RAM voltage is manually set to 1.66 and the QPI to 1.3, if you want to hit 1600MHz or more, which is a fiddle, but still well within the i7’s modest limits.

This will, of course, further crank up the heat, which is where the Trident’s whopping heatspreaders come in. They not only make this the most unusual-looking RAM in this test (mercifully you can’t see too much of that garish red logo once it’s installed), but also the coolest running. The Crucial, meanwhile, ground to a bluescreen halt not far above the official 1600MHz rating – those small spreaders might be better-suited to a cramped case, but they’re ill-suited to overclocking.

Proof in the benches

Still, check those benchmark results – it would appear that doubling the amount of RAM doesn’t make a blind bit of difference. That said, 64-bit fun is slowly on the rise, 6GB kits have dropped in price dramatically, and, when it comes to RAM, there’s no such thing as too much. If you’re running a 64-bit OS and are prone to, say, leaving an MMO alt-tabbed while you’re mucking around in Photoshop, it’s worth going for the big six. Otherwise, you can save yourself a bundle on that expensive Core i7 system you want to build by sticking to just 3GB of RAM. Expect contemptuous stares from the technorati, of course.

For all that, it’s worth pointing out that the Tridents are incredibly well-priced for a 6GB kit rated at an eye-watering 2 000MHz – especially when you consider the absurd $400 tag on the OCZ kit. Where this falls short of that is in latency, which is a pretty unimpressive 9-9-9-24. These drop down to 8s without a problem, but don’t expect to get much lower. Again, QPI limitations mean that mythical 2 000MHz is hard to attain on many X58 motherboards – not the fault of the sticks, but something to bear in mind in case your heart’s sent all a-flutter by that 2GHz rating.

The problem is in the motherboard, not in the memory – unlike the Crucial Ballistix, which hit the heat wall not far above 1700MHz. On the plus side, they do have a choice of cooler-colors if you buy direct from Crucial. They might be slightly less of an overclocker’s dream, but they’re much more of a case-modder’s.

Two surprisingly good value kits, then, from a slice of the memory market that’s generally renowned for being stupidly expensive: DDR3 has finally pulled its head from the clouds, clearly. If you’re toting a high-end motherboard and ideally a Core i7 Extreme, the G.Skills are the ones to go for – they give you a pretty good shot at getting the processor to the fabled 5GHz.

If you’re on a budget, however, $l50 snags you 3GB of Crucial Ballistix. It might sound a whole lot less sexy than 6GB, but realistically you’re not going to notice the difference. On yet another hand, the G.Skills really aren’t that much pricier – and they’re around $70 less than getting 6GB of Ballistix – so if you can round up another $80-odd and are running a 64-bit OS, it’ll be money well-spent.