Test of the Core 2 successor

Intel Core i5 and Core i7: Lynnfield CPUs reviewed

The Core 2 successor has arrived: PC Games Hardware reviews the new Lynnfield also known as Core i5 and Core i7 in form of the Core i5-750, Core i7-860 and the Core i7-870.
Lynnfield reviewed
Lynnfield reviewed [Source: view picture gallery]
Intel's Corei7-900 with the Nehalem architecture definitely is an excellent processor - but up to now it hasn't fit into the market yet. The Bloomfield is primarily at home in servers and workstations and thus not a real successor for the Core 2 - the processors and boards are too expensive. But now Intel introduces the architecture to the mass market: The Lynnfield is launched.

Lynnfield reviewed: Core i5-750
Lynnfield reviewed: Core i5-750 [Source: view picture gallery]
Intel Core i5 and Core i7: Lynnfield introduction
The new processors, codename Lynnfield, will replace the Core 2 Quad as Intel's middleclass CPUs. They are intended for the market sector between 175 and 500 Euros. For the lower prices there will be the Clarkdale at the end of the year, while high-end PC will still be supplied by Bloomfield. Intel also introduced new family brands for the processors and assigned all desktop CPUs with the name Core i3, i5 or i9 - tags like "duo” or "Quad” are cut.

Lynnfield reviewed: Core i5-750
Lynnfield reviewed: Core i5-750 [Source: view picture gallery]
Intel Core i5 and Core i7: Lynnfield architecture - Nehalem light
The Lynnfield architecture is quite similar to Bloomfield, after all both belong to the Nehalem family and are produced in 45 nanometers. Thus the Front Side Bus known from the Core 2 is replaced by DMI. With 2.13 GHz instead of 2.4/3.2 GHz this connection runs slower than the QPI of the Bloomfield and it can't interact with other processors on the motherboard - so the Lynnfield is definitely not the right processor for multi socket systems. Furthermore the integrated memory controller of the Lynnfield supports Dual Channel only.

Besides that there are no significant differences. The three cache levels are as big as those of the Bloomfield (512 KiByte L2 per core and 8 MiByte L3 cache for all cores). The core frequencies of the new CPUs range from 2.67 GHz to 2.93 GHz, but as the Turbo Mode is concerned the Lynnfields have an advantage in comparison to the bigger Bloomfields: While the latter ones can increase the multiplier by two points only, the smaller Lynnfields can already go up four steps and the bigger ones even five.

Another advantage of the new processor is the official compatibility to DDR3-1333, while the i7-900 is restricted to DDR3-1066 - even if more is usually possible. The Lynnfield also has an integrated PCI Express Controller so the processor addresses the graphics card directly. Thus the P55 chip has to deal with the tasks of a classical Southbridge and thus it is a single chip solution - unlike the P55 of the Bloomfield.

Lynnfield reviewed: Cooler comparison: Core i5 (left) and Core 2 (right)
Lynnfield reviewed: Cooler comparison: Core i5 (left) and Core 2 (right) [Source: view picture gallery]
The maximal TDP (Thermal Design Power) of the Lynnfield is set to only 95 watt which is 35 watt less than the TDP of the Bloomfield. But cooling the processor sis made a little more complex because CPU coolers for the sockets 775 and 1366 don't fit onto the new holes of the P55 boards - the 775er is smaller and the 1366er is bigger. Some manufacturers already offer new mounting kits for their CPU coolers.

Intel Core i5 and Core i7: Lynnfield benchmarks
PC Games hardware tested the Core i7-860 and the i5-750 and compared their performance in several games and applications with the results of ten other processors. During our tests SMT was active - as far as the processors support it - but we didn't use the Turbo Mode since the effects of ambient temperature, cooling and voltage supply are too big. Because we only have pre-release samples of the processors we don't deliver results for the temperatures and power consumption. But as a general observation it can be said that a Lynnfield system is more efficient than a comparable Bloomfield setup.

In games we use a resolution of 1680 x 1050 pixels without Anti aliasing or Anisotropic Filtering. As a graphics card we use Geforce GTX 285 with 1,024 MiByte VRAM which is fast enough to make the processors the limiting factor in the game benchmarks.

Intel Core i5 and Core i7: Results
The applications tests reveal the basic power of the Lynnfield: The core i7-860 reaches excellent results and beats the Core 2 Quad. The i7-860 is even slightly faster than the actually bigger i7-920 - not really surprising since the architecture is the same in most parts, but the Lynnfield has slightly higher clock speeds. The i5-750 on the other hand is slower since it doesn't offer Hyper Threading which is supported by all four programs. Thus the smaller Lynnfield only reaches the level of the Core 2 Quad Q9650 and the Phenom II X4 965 BE in the application benchmarks - except Truecrypt where the Phenom II is beating all the other processors.

In our four game benchmarks the bigger Lynnfields also reach the performance of the smaller Bloomfields - i7-860 and i7-920 differ only slightly with small advantages for the Lynnfield. But here Hyper Threading doesn't deliver a benefit but results in a disadvantage: In three games a processor without SMT is leading the board and the i7-860 is beaten by old Q9650 twice. Only Anno 1404 Dawn of Discovery benefits from the four virtual cores and thus the i7 models are winning. But in most games the i5-750 is faster and in GTA 4 and Race Driver: Grid it is even leading the charts. But bear in mind that SMT can be deactivated - so you should consider to do it if you primarily use your PC for gaming.

Core i5-750
Core i5-750 [Source: view picture gallery]
Intel Core i5 and Core i7: Overclocking
With a slightly increased voltages we try to test the OC capabilities of our Core i5-750: Prime 95 was running stable at 3800 MHz (190 x 10) with 1.25 volt, while we had to go to 1.3125 volt to get 4000 MHz stable. In our benchmarks 1.2875 volt were enough. 4200 MHz (210 x 20) are not for all day usage since the required increase for the voltage results in temperature problems and crashes.

As overclocking is regarded the bigger Core i7-860 differs little from the i5-750. In the lower frequency area a lower voltage was sufficient. To get 4200 MHz stable in benchmarks the IMC voltage had to be set to 1.225 volt though.

For a pre-release sample those overclocking capabilities are quite impressive - good cooling is required nevertheless. But for most users it will be enough to activate the Turbo Mode in the BIOS and have the CPU choose the best frequency. Either way more than 3 GHz are easy to reach but not necessary for gaming.

Lynnfield reviewed: Core i5-750
Lynnfield reviewed: Core i5-750 [Source: view picture gallery]
Intel Core i5 and Core i7: Lynnfield Conclusion
The Lynnfield is a worth successor to the Yorkfield. As Core i5-750 as well as Core i7-860 the new core shows that it is not inferior to the expensive Bloomfield. The performance benefit might not be as big as it had been from the Pentium D to the Core 2, but it is noticeable in almost every test. The price is another advantage of the Lynnfield. A Core i5-750 costs about 175 Euros and a P55 board about 90 Euros - so it is possible to assemble a comparatively low priced gaming system. IF you want to spend even less money you will have to wait for the Clarkdale - or take a look at the products of Intel's competition.

Picture gallery  (enlarge to view source)

Author: Schröder, Sauter (Sep 08, 2009)

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