Posts Tagged ‘Comparison’

Choosing a new CPU: Intel Core i7-920/930 vs. i7-860/870

[tweetmeme source=”KeithBluestone” only_single=false]This article is part of a series in 2010 on custom-building a high-performance computer with the latest Intel Core i7 processors:

  1. Build or buy a new Core i7 supercomputer?
  2. Choosing a New CPU: Intel Core i7-920/930 vs. i7-860/870
  3. New Core i7 PC: Selecting the Components
  4. New Core i7 PC: The Build

[Update 8/25/2010: the Core i7-870 is now available and has matched the price point of the i7-860. It’s absolutely identical to the i7-860 except that it runs at 2.93 GHz instead of 2.8 GHz. ]

[Update 3/21/2010: the Core i7-930is now available. It’s absolutely identical to the i7-920 except that it runs at 2.8 GHz instead of 2.66 GHz. Where I mention the i7-920 by name, it also applies to the i7-930.]

Overview

imageThe new Intel Core i7-920/i7-930 and i7-860/i7-870 processors are extremely close in most aspects,  but the i7-920/930 offers features that only enterprise users, professional videographers, or heavy gamers will need.   The i7-860/870 matches or betters the i7-920/930 in almost all benchmarks – and uses less power!

So unless you have an extreme need, you can save a few bucks with the i7-870 and plow it back into more memory, a faster/bigger/more reliable hard drive, or a better graphics card.

Note from the future: Don’t forget the CPU cooler!

Quad-core: the current sweet spot

Currently, my choice for a reasonably snappy system with a life expectancy of around five years is an i7-870 or an i7-930.  The higher-performing, extreme versions of these processors cause the price to shoot radically upwards.  Why pay for that performance when overclocking will accomplish the same thing?

In a related blog post,  I made the case for upgrading to the latest and greatest processors instead of taking advantage of fabulous deals on enterprise-class computing hardware on eBay.   In short, the newest Intel Core i7-family processors have much to offer over older processors, including improved power efficiency, general computing power and flexibility, and total cost of ownership (TCO).     Both processors have support for virtualization (VT), allowing you to host a virtual computer within these systems that looks like a real, separate PC.

These processors both have four physical cores, and with Intel’s HyperThreading technology, these four cores appear as eight separate processors to the operating system.  The new Nehalem processor architecture improves memory speed (latency and bandwidth), which can be a major performance bottleneck as improvements in the speed of processors over the last thirty years have far outpaced those in the speed of memory chips.

Why multi-core computing is such a good idea. Somewhere around mid-2004, Intel introduced the first dual-core processors for the desktop, initially in high-end systems and gradually working their way into most computers.  One main reason these multi-core systems (especially a quad-core) are going to be so much more responsive than your old single-core Dell is because there are simply more applications and background processes running on a modern computer.  And they all chew up available processor power.  In particular, big anti-virus suites (Norton, Symantec) are some of the worst offenders: in troubleshooting systems for friends and family, I’ve seen them consuming up to 100% of CPU cycles.  But why get mad?  Get even.  With a properly spec’d quad-core box you’ll have plenty of capacity to run everything.  Chances are, you won’t even notice it’s there.  (Make sure you have enough memory!  At the date of this writing – June 2010 -  you should have no less than 4GB RAM.)

So which processor to get:  the i7-930 or the i7-870? In a nutshell, you could probably quit obsessing over the details, buy either one and get about the business of enjoying your snappy new PC.   For me, being a detail-oriented software architect who specializes in high-performance and high-throughput architectures, I wanted to understand the finer differences between the two and make an informed decision.

Quad-core Nehalem architecture

Quad-core Nehalem architecture

Analysis

First of all, the processors’ names are more or less no help to us. You might think that the “i7-9×0” is a later, more advanced version of whatever the lesser “i7-8×0” might be.   But understanding Intel’s processor nomenclature and numbering system is a reasonably sized effort in itself, and in this case, 930 is not necessarily greater than 870.

After several days of trawling through a ton of web pages, from Intel’s site (very good!) to AnandTech to Tom’s Hardware to discussion forums, these are my conclusions.

The prime differences, with the winner in each category, would seem to be:

  • Clock speed (i7-870).  The i7-930 runs at 2.8 GHz vs.  the i7-870 at 2.93 GHz, giving the i7-860 about a 5% advantage in raw clock speed, plus a more aggressive turbo mode which pushes the i7-870 to a max of 3.6 GHz vs. the 930’s max of 3.06 GHz – almost a 20% increase.
  • Power consumption (i7-870).  The i7-930 has a TDP of 130W, which is about 50% higher than the i7-870 at 95W.   In AnandTech’s benchmark reference systems, the i7-860 system at idle uses 85W and the i7-920 system uses 115W;  see the AnandTech i7-860 review, power consumption page.   At about $1 per watt-year over a computer lifetime of 5 years, 30W could cost you up to $150 more.
  • imageMotherboards (i7-870). Motherboards  for the i7-8×0 Lynnfield processor family (socket LGA 1156) are less expensive and more prevalent than for the i7-9×0 Bloomfields (socket LGA 1366).
  • Overall system throughput (i7-930). The i7-9×0 has a faster bus speed, utilizing a QPI bus with a max bandwidth of 4.8 gigatransfers per second (GT/s).   The i7-8×0 uses a DMI bus with a bandwidth of 2.5 GT/s.  However, this is only an advantage if you’re maxing out the bus… rare unless you’re in an enterprise server setting or doing graphics or other data/compute-intensive work.  According to the Intel specs, the i7-9×0 also has 20% higher memory bandwidth (25.6 GB/s) than the i7-8×0 (21 GB/s), also important for high-performance applications.
  • Extensibility (i7-930). The i7-9×0 enables direct dual PCI-e for crossfire & SLI applications: important to gamers mostly for high-performance graphics setups.

Drawbacks

Neither of these processors supports ECC memory.  This is not a huge issue for most folks, but for the more critical and most stable systems (servers and scientific computing installs), ECC memory protects against data corruption caused by – believe it or not – cosmic rays.

Conclusions

While again you could probably go out and buy either the Core i7-870 or the i7-930 and be happy, I found little to justify the i7-930 over the i7-870 in general, with the exception of the truly hard-core crowd.


How to Buy

My first choice for PC hardware is NewEgg.com, which has an excellent online store, good prices, and fantastic customer service.

Naturally, you can also find pre-built Core i7-based systems at Dell and other vendors;  for example, the Studio XPS systems.

  • Also: Xeon X3440 on NewEgg.com ($240).  As mentioned above, the X3440 is the rough equivalent of the i7-860 (Lynnfield core), but supports ECC RAM.

References