The Ultimate Computer Hardware Guide: Page 5

RAM 

System RAM, or memory, seems like such a basic thing, but there’s still much to know about it

Clock Speed 

The clock speed of RAM is usually expressed in megahertz, so DDR3/1866 runs at 1,866MHz, at a certain latency timing. The only problem is that modern CPUs pack so much cache and are so intelligent in managing data that very high-clocked RAM rarely impacts overall performance. Going from, say, DDR3/1600 to DDR3/1866 isn’t going to net you very much at all. Only certain bandwidth-intensive applications such as video encoding can benefit from higher-clocked RAM. The sweet spot for most users is 1,600 or 1,866. The exception to this is with integrated graphics. If the box will be running integrated graphics, reach for the highest-clocked RAM the board will support and you will see a direct benefit in most games.  

Channels

Modern CPUs support everything from single-channel to quad-channel RAM. There isn’t really a difference between a dual-channel kit and a quad-channel kit except that the vendor has done the work to match them up. You can run, for example, two dual-channel kits just fine. The only time you may want a factory-matched kit is if you are running the maximum amount of RAM or at a very high clock speed.

Voltage

Voltage isn’t a prominent marketing spec for RAM but it’s worth paying attention to, as many newer CPUs with integrated memory controllers need lower-voltage RAM to operate at high frequency. Older DDR3, which may have been rated to run at high frequencies, could need higher voltage than newer CPUs are capable of supporting.

Heatspreaders

Heat is bad for RAM, but we’ve never been able to get any vendor to tell us at what temperature failures are induced. Unless you’re into extreme overclocking, if you have good airflow in your case, you’re generally good. We’ve come to feel that heatspeaders, for the most part, are like hubcaps. They may not do much, but who the hell wants to drive a car with all four hubcaps missing?

Capacity, Registered DIMMs, and Error Correction

It’s pretty easy to understand capacity on RAM—16GB is more than 8GB and 4GB is more than 2GB. With unbuffered, nonregistered RAM, the highest capacity you can get to run with a consumer CPU are 8GB modules. Registered DIMMs, or buffered DIMMs, usually refers to extra chips, or “buffers,” on the module to help take some of the electrical load off the memory controller. It’s useful when running servers or workstations that pack in a buttload of RAM. ECC RAM refers to error-correcting control and adds an additional RAM chip to correct multi-bit errors that can’t be tolerated in certain high-precision workloads. If this sounds like something you want, make sure your CPU supports it. Intel usually disables ECC on its consumer CPUs, even those based on the commercial ones. AMD, on the other hand, doesn’t. For most, ECC support is a bit overkill, though.

We’re not sure what RAM heatsinks do today except look cool.

Power Supply Unit

The power supply doesn’t get all the attention of, say, the CPU or the video card, but disrespect the PSU at your own peril

Wattage

The actual wattage of the PSU is the spec everyone pays attention to. That’s because 650 watts is 650 watts, right? Well, not always. One maker’s 650 watts might actually be more like 580 watts or lower at the actual temperature inside your case on a hot day. Despite all this, the wattage rating is still one of the more reliable specs you can use to judge a PSU. How much you need can only be answered by the rig you’re running. We will say that recent GPU improvements have caused us to back away from our must-have-1,000W-PSU mantra. These days, believe it or not, a hefty system can run on 750 watts or lower with a good-quality PSU.

Efficiency

After wattage, efficiency is the next checkmark feature. PSU efficiency is basically how well the unit converts the power from AC to DC. The lower the efficiency, the more power is wasted. The lowest efficiency rating is 80 Plus, which means 80 percent of the power at a load of 20 percent, 50 percent, or 100 percent is converted. From there it goes to Bronze, Silver, Gold, and Platinum, with the higher ratings indicating higher efficiency. Higher is better, but you do get diminishing returns on your investment as you approach the higher tiers. An 80 Plus Silver PSU hits 88 percent efficiency with a 50 percent load. An 80 Plus Platinum hits 92 percent. (Efficiencies for the higher tiers vary at different loads.) Is it worth paying 40 percent more for that? That’s up to you.

Single-rail vs. Multi-rail

A single-rail PSU spits out all the power from a single “rail,” so all of the 12 volt power is combined into one source. A multi-rail splits it into different rails. Which is better? On a modern PSU, it doesn’t matter much. Much of the problems from multi-rail PSUs were in the early days of SLI and Pentium 4 processors. PSU designs that favored CPUs, combined with the siloing of power among rails, proved incapable of properly feeding a multi-GPU setup. Single-rail designs had no such issues. These days, multi-rail PSUs are designed with today’s configs in mind, so multi-GPUs are no longer a problem.

Intelligent vs. Dumb

A “dumb” power supply is actually what 99 percent of us have: a PSU that supplies clean, reliable power. An “intelligent” PSU does the same but communicates telemetry to the OS via USB. Some smart PSUs even let you adjust the voltages on the rails in the operating system (something you’d have to do manually on high-end units) and let you control the fan temperature intelligently, too. Do you need a smart PSU? To be frank, no. But for those who like seeing how efficient the PSU is or what the 5-volt rail is, it’s pretty damned cool.

Modular vs. Non-modular

Modular PSUs are the rage and give you great flexibility by letting you swap in shorter cables, or cables of a different color, or to remove unused cables. The downside is that most high-end machines use all of the cables, so that last point in particular is moot—what’s more, we think it’s too easy to lose modular cables, which sucks.

Modular power supplies are the rage today—just don’t misplace the cables.

System Specs 

How to dole out system advice like a pro

Warning: As a PC expert, you will be called upon often by family and friends for system-buying advice. After all, purchasing a new PC retail can be a daunting task for the average consumer. Remember, you might know the difference between an AMD FX-8350 and FX-6100, but will Aunt Peg?

This machine is probably too much PC for Aunt Peg to handle.

No, Aunt Peg will walk into the local Big Box with the goal of spending $750 on a basic all-in-one and end up walking out with a $3,000 SLI rig. We’re not saying that Aunt Peg doesn’t like getting her frag on as much as the rest of us, but let’s face it, she needs some basic buying tips. 

CPU

Peg, what level of CPU you require depends on your needs. If your idea of a good time is Bejeweled, email, and basic photo editing, a dual-core processor of any model except Atom is more than enough. If you’re looking for more performance, the good thing is that Intel and AMD’s model numbers can mostly be trusted to represent actual performance. A Core i5 is greater than a Core i3 and an A10 is faster than an A8. If you are doing home video editing, Peg, consider paying for a quad-core CPU or more.

RAM

There are three known levers pulled when convincing consumers to buy a new PC: CPU, storage size, and amount of RAM. You’ll often see systems with low-end processors loaded up with a ton of RAM, because someone with a Pentium is really in the market for a system with 16GB of RAM (not!).  For most people on a budget, 4GB is adequate, with 8GB being the sweet spot today. If you have a choice between a Pentium with 16GB and a Core i3 with 8GB, get the Core i3 box.

Storage

Storage is pretty obvious to everyone now, and analogous to closet space. You can never have enough. What consumers should really look for is SSD caching support or even pony up for an SSD. SSD caching or an SSD so greatly improves the feel of a PC that only those on a very strict budget should pass on this option. SSDs are probably one of the most significant advances to PCs in the last four years, so not having one is almost like not having a CPU. How large of an SSD do you need? The minimum these days for a primary drive is 120GB, with 240GB being more usable.

GPU

There’s a sad statistic in the PC industry: Americans don’t pay for discrete graphics. It’s sad because a good GPU should be among the top four specs a person looks at in a new computer. Integrated graphics, usually really bad Intel integrated graphics, have long been a staple of American PCs. To be fair, that’s actually changing, as Intel’s new Haswell graphics greatly improves over previous generations, and for a casual gamer, it may even finally be enough. Still, almost any discrete GPU is still faster than integrated graphics these days. Aunt Peg might not play games, but her kids or grandkids might and not having a GPU will give them a frowny face.  A GeForce 650 or Radeon HD 7770 is a good baseline for any machine that will touch games.

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