A pack of processors
Your choice of CPU can have long-lasting repercussions on your network's performance, security and power use
- By Edmund X. DeJesus
- Jan 31, 2008
Too often, when an agency or department buys a fleet of computers, little attention is given to the type of processor inside. As long as it can run the necessary applications, the cheapest processor frequently gets the nod. Too bad.
However, the choice of processor can have a tremendous impact on the way an organization works and its bottom line. Picking the right processor for servers, for example, can result in smaller, more energy-efficient data centers.
The right server processor can also mean easier management, more uptime, better performance for users and, ultimately, a greater return on investment.
Servers aren't the only platform for which chip choice is important. Even for desktop PCs and portable computers, there are advantages to choosing the correct chip, including reduced power costs, enhanced security and simplified remote management. And for laptops, the choice of processor can make a huge difference in the amount of work you can do on a single battery charge.
Smart agencies look for the right chips ' or, rather, the right benefits that chips can give them. 'Sometimes agencies request specific chips, but more usually they request specific features, such as speed or power,' said Jason Davis, a technical specialist at reseller CDW Government.Chip evolution
We didn't always have such an impressive list of variables to consider. Not long ago, it was all about the gigahertz, and buyers generally made a simple comparison of processor speed to price.
The result was that vendors such as Intel and Advanced Micro Devices cranked up their processor speeds every year. All that electricity pouring into the chips made them run hotter ' requiring more and better cooling or raising the risk of meltdowns. Data centers needed to install stronger air conditioning systems to handle the heat. In laptop PCs, batteries got sucked dry quickly.
More recently, however, new hardware and software developments have altered the processor picture radically. For instance, low-power chips have the double advantage of reducing electricity demands and lowering operating temperatures, which saves money in providing electrical power and removing waste heat.
What impact does power have on operating temperature? According to AMD, a typical 32-watt laptop chip runs at about 127 degrees Fahrenheit, and a typical desktop 85-watt chip runs at a blistering 160 degrees.
And low power doesn't necessarily imply low performance. Most low-power processors are right in the middle of the performance spectrum ' maybe not the fastest chips on the block, but not the slowest either. Even so, processor vendors often mitigate the not-as-fast speeds by including more cache memory on the processor for higher efficiency.
At the same time, new processor fabrication processes are altering chip real estate. For example, Intel's latest generation of processors uses the company's new 45-nanometer process, which allows the tiny transistors to be closer together. As a result, even though the chip is designed to use less power, it still runs faster.
All those extra transistors can provide more floating-point processing and more memory on the CPU for faster data access. It's hard to beat Intel's latest offerings if pure performance is your goal.
Similarly, AMD's switch from 90-nm to 65-nm fabrication for Athlon X2 64 processors cut the power requirements from a range of 89 to 110 watts to 45 watts while lowering speeds only slightly, from 2.4 GHz to 2.3 GHz on the high end.
Of course, you pay a price for new technology, but that small one-time cost can amortize well over years for a fast, low-power processor.
'Moving from a 65-nm chip to a 45-nm chip gives a 50 to 70 percent boost to performance,' said Shannon Poulin, director of Xeon platforms at Intel. And even more compact fabrication, at 32 nm, is on the horizon.
The advent of multicore chips is also having a major impact on the design of servers and laptop and desktop PCs.
Strictly speaking, we've already had multicore processors for a while, ever since the introduction of dual-core chips. However, the recent launch of quad-core chips ' with four physical processors on the same die ' and the prospect of eight-core and even more advanced designs adds ever more options for agencies. For instance, the idea of replacing four single-cores or two dual-cores with a single quad-core processor is attractive for large data centers.
What's more, chip designers are increasingly building security and management features into the processors. When those functions are implemented in hardware, of course, they can't be circumvented easily and are less of a drain on processor resources.Server savvy
How do these new technologies and strategies apply in the real world of computer acquisition? Let's start with servers.
'Chip choice is a significant part of a server price,' said Kevin Van Mondfrans, group product marketing manager for Hewlett-Packard's ProLiant line of servers.
In general, AMD's prices are likely to be more attractive than Intel's. Even so, the price of the chip shouldn't be your sole consideration. You want to acquire the benefits that will make the most economic and processing sense, not just now, but also three to five years from now. And that means making educated choices about how various processors' features will match your future requirements.
Suppose you want to cut power requirements for your server farm ' a goal that can be critical, whether you know it or not. Van Mondfrans has seen customers who can't supply power to a whole server rack because they haven't paid attention to their power needs.
Energy-efficient chips can make a big dent in power consumption ' and costs. 'Agencies are willing to pay a small premium for lower power,' Van Mondfrans said.
Lower power requirements can also produce other hidden benefits, especially for server farms.
By reducing the heat that processors produce, you remove the necessity for costly and disruptive installation of better cooling equipment.
You also lower the long-term costs for that cooling.
And in searching for the right server processor, don't get overly distracted by clock speed. 'Most new processors are multicore, so clock speed isn't as important as it used to be,' said Roger Kay, president of consultant Endpoint Technologies Associates.
Look for vendor-independent standards and ratings for power and heat so you can keep your systems within a defined power/temperature envelope. Also, vendors realize the significance of power consumption and heat, and many provide online configuration tools to help you select the best chip for your needs.
You'll also want to consider physical infrastructure plans as you select processors. Many agencies are feeling pushed ' both by security concerns and cost-cutting initiatives ' to consolidate their data centers. The right choice of processors can help.
By replacing single or dual cores with quad cores, you can shrink the server space necessary.
If your agency is considering such consolidation, plan carefully for the quad-core chips' needs. For instance, moving from dual cores to quad cores could require double the memory for each chip ' or more.
It's somewhat paradoxical that an agency could need to move to a bigger platform to consolidate.
'People don't buy less machine because of multicores, although they may buy fewer,' Van Mondfrans said.
Virtualization is another strategy for consolidation.
By using virtualization, one processor can do the work of several, reducing the number of processors required. 'Agencies want the most out of their servers,' Davis said, and virtualization is one path to that goal. If it's part of your path, you'll want to consider Intel processors with embedded virtualization features.
Rather than poking along with utilization rates of 20 percent to 40 percent, you could be looking at 80 percent or 90 percent.
There is tremendous synergy between multicore chips and virtualization. Those extra cores can be running different virtual process threads.
Microsoft Windows natively splits tasks between cores so the processing is transparent to users. As a result, agencies can maximize output and performance. Another plus is that software licenses are often per-socket, not per-thread, which can further reduce costs.
Once you've scoped out the relative importance of price, performance, power consumption, heat generation and consolidation potential, you're ready to go shopping. Take your calculator with you. Vendors offer a dizzying array of options. You'll find it easier if you compare your needs assessment first to the processor families offered by vendors and only after that consider specific processors.
For the most intensive server workloads, the Intel Itanium 9000 sequence offers massive parallelism scalable to as many as 512 processors.
The 13 chips in this sequence are mainly 104 watts ' two are 75 watts ' and offer speeds from 1.4 GHz to 1.66 GHz and caches from 8M to 24M. An older chip, the 9000 doesn't offer anything special for virtualization.
The price ranges from $696 to $3,692 for the fastest entry with the most memory.
At the enterprise server level, if power is no object, the quad-core Intel Xeon MP X7350 offers 2.93 GHz speeds and the best virtualization in the Intel line ' at 130 watts and about $2,301. At the lower end of the power scale in the same 7000 sequence, the quad-core Xeon MP L7345 runs at a respectable 1.86 GHz at only 50 watts.
The quad-core AMD Opteron 8300 series corresponds to the Intel Xeon 7000 sequence but with lower power demands ' and lower prices. These processors include the 2-GHz 75-watt 8350 at about $1,019 and the 1.9-GHz, 55-watt 8347 HE for about $873.
For midsize servers, the quad-core Intel Xeon 5400 series includes 13 of the 80-watt, 45-nm choices with virtualization features, from the zippy 3-GHz E5472 at about $1,022 to the 2-GHz E5405 at about $259.
Similarly, the quad-core AMD Opteron 2300 series corresponds to the Intel Xeon 5000 sequence, again with lower power needs and prices. For example, the 2-GHz, 75-watt 2350 costs only $389, and the 1.9-GHz 2347 HE requires a minuscule 55 watts and costs $377.
With smaller servers suitable for small offices or dedicated mail and print services in large installations, the Intel Xeon 3000 sequence includes three 95-watt chips with 45-nm technology and virtualization, from 2.5 GHz to 2.83 GHz from about $224 to $530.Desktop and laptop PCs
The math is similar when you go shopping for desktop and laptop PCs for your agency or department, though some of the variables will change.
As noted above, for example, power requirements have even more obvious repercussions for laptops than for desktop PCs because lower processor power requirements translate directly into longer battery life.
AMD's desktop-oriented Athlon 64 X2 dual-core chips would be tough on a battery because they can consume from 89 to 125 watts and run from 2 GHz to 3.2 GHz. By comparison, the AMD Turion 64 X2 is a dual-core chip that only uses 31 to 35 watts to run from 1.6 GHz to 2.2 GHz.
Intel offers similar choices. Its Core 2 Merom dual-core chip uses 35 watts to run from 2 GHz to 2.6 GHz. A low-voltage version of the Merom uses half the power and runs at 1.33 GHz to 1.8 GHz. That simple choice can quadruple your battery life and keep your thighs from getting scorched.
Desktop PCs can also enjoy benefits from the right processor picks. They run for a long time each day, so reducing their power consumption cuts costs significantly.
Also, moving to multicore chips gives a definite boost to running applications. Moving from a dual core to a same-speed quad core roughly doubles performance.
For both desktop and laptop PCs, buyers will want to consider the management capabilities of processors.
Intel's on-chip vPro technology for remote management can be attractive for managing large numbers of desktop PCs. For example, the Veterans Affairs Department is replacing 240,000 desktop PCs. They want vPro to lock down computers for the night, saving power and improving security.
Using vPro configurations, agencies can ensure that computers don't get on the network unless they have the proper credentials. For large organizations, vPro enables simpler centralized management that is independent of operating systems and applications.
There are many software-based remote management solutions, but Intel's vPro is unique among chip vendors.
On the other hand, if your agency has already standardized on a software-based management system, you may want to forgo the additional cost of a hardware-based solution.The bottom line
The bottom line is to be aware of the bottom line.
Processor selection will have a long-standing impact not only on the performance of computers in your agency or department but also on overall energy costs and manageability. Be clear about your priorities before shopping for the right match.