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Intel Lynnfield Core i7-870 and Core i5-750 Processor Review

Author: Ryan Shrout
Subject: Processors
Manufacturer: Intel
Tagged:

The Core i7-870 and Core i5-750 CPUs

The new Lynnfield processors, that fall into both Core i7 and Core i5 brands, are a completely new package design and socket design known affectionately as LGA1156.  That means of course you will need a new motherboard and a new cooler (more than likely) to go along with any Lynnfield processor purchase; good news for companies like ASUS, Gigabyte and MSI, but bad news for anyone else.



From left to right: Intel Core 2, Intel Nehalem, Intel Lynnfield, AMD Phenom



From left to right: Intel Core 2, Intel Nehalem, Intel Lynnfield, AMD Phenom

You can see in these photos that the Lynnfield CPUs are physically identical in size to the Intel Core 2 Duo/Quad processors and smaller than the LGA1366 Nehalem core parts.



Lynnfield over Nehalem, deuces are wild



Stock retail coolers from Intel; Lynnfield on the left, Nehalem on the right

Lynnfield-based processors all have a significantly lower TDP (thermal dissipation profile) than Nehalem processors as is evident by comparing the stock Intel coolers for the two parts.  The retail Lynnfield cooler is significantly lower profile and lighter but was still able to get the job done.

The table above shows us a few things including model numbers and naming schemes, clock speeds, Turbo Mode speeds, thread counts and more.  Let's start with the names and branding first, as it all mixes together quite nicely.  For today's release Intel has a pair of Core i7 processors, the Core i7-870 and the i7-860, both of which are quad-core processors with HyperThreading enabled to support 8 threads.  The Core i5-750 is a quad-core part without HyperThreading but with the same 8MB L3 cache as the Core i7 offerings.  Essentially, any Lynnfield processor that does have HyperThreading technology enabled is a Core i7 part; those without it are Core i5 or below.

The base frequencies of these processors are in 133 MHz steps starting with the Core i5-750 @ 2.66 GHz and going up to 2.93 GHz on the Core i7-870.  What is really more important though is the Turbo Frequencies listed here as you will likely very rarely see your CPU actually running at that base clock speed.  Why?  Check the series of CPU-Z images below:



Idle

Here we have the Core i5-750 sample sitting at idle on our Windows 7 x64 RTM system running at only 1.2 GHz - this is one of the benefits of Intel's SpeedStep technology that permits lower idle power consumption and lower heat. 



Core i5-750 CPU with 4 threads working

Remember that in that table above, the Core i5-750 was rated at "up to 3.2 GHz" with Turbo Mode technology.  Here you can see how the processor responded with four working threads keeping the CPU 100% loaded: the processor was running at 2.8 GHz and did so every time.



Core i5-750 CPU with 1 thread working

With just a single thread at work though, the Core i5-750 hit the 3.2 GHz mark - this is why Intel is giving out a range of frequencies for Turbo Mode.  Depending on the current thermal levels of the processor, its environment and cooling capacity, the system is supposed to dynamically adjust the frequency accordingly.



Core i7-870 CPU with 8 threads working



Core i7-870 CPU with 1 thread working

The higher-end Core i7-870 processor runs at 3.2 GHz when fully loaded with 8 threads (or 5+ for that matter) and at 3.6 GHz when only a single threaded application is at work.  The benefit of this of course is that Lynnfield should actually be able to best the Nehalem in some single threaded performance results since the Core i7-975 runs at only 3.46 GHz with Turbo Mode enabled.

Now, let's look at pricing on these new processors released today.  Intel sent us one of the Core i7-870s and one of the Core i5-750s; the highest and lowest priced Lynnfield CPUs available at launch.  The i5-750 will definitely be the lowest cost processor with these performance levels available anywhere.  By jumping up another $85 or so you can get a slightly higher base clock and Turbo Mode speeds as well as the added performance of HyperThreading.  Moving up to the i7-870 will cost you $270 more but only get you a single stepping higher performance (133 MHz in base and Turbo Mode speeds) which definitely make the i7-860 the best overall value at first glance. 

We will have to see how performance pans out though...

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