RAM(DDR4 RAM)

 Over the past year, desktop PCs have seen plenty of change. Systems have been shaken up by new processors, chipsets and sockets, and all of that has happened hand-in-hand with the arrival of DDR4 memory. 

    These upgraded chips look much the same as older DDR3 modules, but offer improved speed and capacity – both of which make them a tempting addition to a new system, or a worthwhile upgrade to an existing build.

There are numerous options for DDR4 out there, with different speeds, capacities and prices on offer. I’ve gathered nine kits from four manufacturers to find out which are worth buying.

1. CORSAIR DOMINATOR PLATINUM 16GB 3000MHZ
2. CORSAIR VENGEANCE LPX 8GB 2666MHZ
3. G.SKILL TRIDENTZ 16GB 3200MHZ
4. KINGSTON HYPERX SAVAGE 8GB 3000MHZ

DDR4 MEMORY EXPLAINED

There are several fundamental differences between new DDR4 memory and the DDR3 variant that’s been used for the past eight years.

The most obvious is speed. Older DDR3 modules usually run between 800MHz and 2,133MHz, but it's at this latter figure that DDR4 begins. There are already modules available at speeds beyond 3,000MHz, with market-leading kits clocking in at 3,866MHz. If the development of DDR3 is any indication, I expect that manufacturers will go even further by overclocking their memory.

DDR4 modules are also capable of offering far larger capacities than DDR3 modules – 512GB rather than 128GB – but, for the foreseeable future, this is an advantage that will remain theoretical for home users.

DDR4 DIMMs have a distinctive bulge in the centre of the pins

The new modules provide a speed boost while also consuming less power. Older DDR3 modules required 1.5V of electricity to function, while DDR4 DIMMs need only 1.2V. This isn't a huge difference, but it’s enough to slightly reduce PC power consumption – and the more memory inside a PC, the larger that reduction will become.

On the whole it's good news, then, except for one department: latency. This refers to the speed at which read requests are answered by the memory. Older DDR3 chips answered calls in 13.75ns, which is referred to as CL11, but most DDR4 chips function at CL15 – which means a latency of 14.06ns. That’s a tiny difference that won’t be noticeable in the real world, especially as the increased speed of DDR4 should pick up the slack.

PROCESSORS, CHIPSETS AND MOTHERBOARDS – USING DDR4

There’s no doubt that DDR4 memory is far better than its predecessor, but these newer products work with a smaller range of compatible hardware.

At present, DDR4 works only with Intel’s Haswell-E and Skylake processors. The former chips are Extreme Edition parts that range in price between rs20,000 and rs60,000, and they’re really only suitable for high-end work tasks that demand six or eight cores. The Skylake range is far broader: chips with Pentium, Core i3, Core i5 and Core i7 branding all use the Skylake architecture and support DDR4

The Haswell-E and Skylake processors that work with DDR4 also bring different chipsets to the fore. The X99 silicon that works with Haswell-E processors was the first commercial chipset to support DDR4, and it can handle the new memory chips in dual- or quad-channel modes. As a result, PCs can use two or four sticks of memory at once.

It’s a little different with Skylake and its Z170 chipset. That part supports only dual-channel DDR4, and any build will be restricted to sticks of memory that operate in pairs. So, a system can have four sticks of memory but they’ll work in sets of two, rather than in a single rack of four.

On paper, both Haswell-E and Skylake chipsets support DDR4 that runs at 2,133MHz, but motherboard manufacturers muddy those waters by engineering their boards to run DDR4 at higher speeds – which is why every kit I’ve tested in this group runs at 2,400MHz or higher.

Aside from that, however, it’s business as usual when it comes to buying a motherboard to work with DDR4 memory. As long as it’s a Haswell-E or Skylake-compatible board then DDR4 will work.

Memory technology over the years

In addition, fitting sticks of memory is as easy as it’s ever been: simply open the plastic gates at the end of the DIMM slot and push in the DDR4 until it clicks into place. Just make sure that the indentation on the stick of memory lines up with the raised area on the motherboard slot.

It shouldn’t take too much work to get DDR4 working at the correct speed. Some motherboards play it safe by defaulting to a lower speed. To check that memory is running correctly, head into the BIOS – memory speeds should be displayed on the front page. If it’s incorrect, open the Advanced menu and head towards the tweaking section. There will likely be an option for DRAM frequency; set this to the DDR4’s rated speed, save the changes and reboot.

The situation isn’t as good for AMD-based users. The firm’s current FX CPUs use the Vishera architecture, and its APUs use Kaveri, but neither of those support DDR4 – they’re both stuck with DDR3.

The only way to use DDR4 on AMD right now is to use obscure embedded chips, because they’re the only parts to deploy the more modern Excavator architecture. The best bet for consumers on AMD is to wait for its Zen architecture, which is scheduled for release in October 2016 across a wide range of consumer desktop and laptop components.