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Thermals
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Core Temperatures
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Test State
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i7-870
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i5-750
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Stock
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UV
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Stock
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UV
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Core 0
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56°C
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49°C
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54°C
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47°C
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Core 1
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50°C
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43°C
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49°C
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43°C
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Core 2
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56°C
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49°C
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54°C
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48°C
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Core 3
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50°C
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44°C
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46°C
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40°C
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Average
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53°C
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46°C
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51°C
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45°C
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Thermalright MUX-120 with stock fan @ 5.6V (900 RPM).
Ambient temperature: 22°C.
i7-870 undervolted to 1.025V stable (~1.1375V stock).
i5-750 undervolted to 1.0625V stable (~1.1625V stock).
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In our open testbed, cooled by a Thermalright MUX-120 heatsink using the stock
fan running at 900 RPM, the core temperatures (as reported by Core Temp and
SpeedFan) were fairly low. Both processors averaged in the low 50's when placed
under full load with Prime95. Undervolting cooled temperatures by 6-7°C.
The heatsink barely felt warm during testing — it shouldn't be difficult to
cool these processors quietly, but early adopters will have to wait for more
cooling options to be released.
Motherboard Impressions
Our Intel DP55KG was a pre-production sample using the latest BIOS provided
by Intel. It was quirky compared to most of the retail boards we've reviewed
in the past. At first we used regular Corsair XMS3 memory, but the board refused
to POST. We switched to XMS3 DHX, and it worked fine. After changing some minor
settings in the BIOS, it again failed to POST, and required a BIOS reset. When
we added a second stick of XMS3 DHX, the board again protested. In the end,
we used two sticks of XMS3, which worked with a voltage increase, however, they
would only function properly in the blue slots, not the black. Also, when we
switched processors (even though we set the CPU settings to Automatic), we had
to reset the BIOS once again. All in all, a rather frustrating experience. Luckily
there is an error code display directly on the PCB. Other than the above problems,
there were no stability issues and the board's VRM and chipset heatsink stayed
lukewarm during testing.
The BIOS allowed for 3-pin and 4-pin control on three fan headers, though the
CPU fan header generated an odd buzzing noise when used with the Thermalright
MUX-120's stock PWM fan (swapping the fan or header resolved this issue). Incidentally,
SpeedFan's current version, 4.39, does not support this board. The frequency
and voltage options were liberal. You can change how much increase Turbo Boost
provides, and you can vary the resulting speed depending on how many cores are
in use. When you override the CPU voltage, you can leave SpeedStep on, so a
lower idle CPU voltage is achieved when undervolting. VDroop can also be adjusted
— the default setting is high which makes for lower power consumption.
For more stable overclocking, it should be set to low.
FINAL THOUGHTS
Despite some hassles with a quirky motherboard, our experience with the new
Lynnfield processors were mainly positive. They do not offer the kind of performance
increase that LGA1366 brought to the table, but they bridge the gap
between Core 2 Quads and the Bloomfield
i7's. We were far more impressed with the energy efficiency of the i7-870 and i5-750 samples. Not only did they
use less power than their LGA775 counterparts, they even managed to beat out the
Q9550S, a high efficiency 65W part. As a
bonus, they also displayed some undervolting potential. Cooling a Lynnfield
processor should be a fairly trivial matter.
If you already have a fairly high speed quad core setup, there isn't any reason
to jump ship to LGA1156. However, if you're aching to upgrade from a single
or dual core system and energy efficiency is high on your wishlist, a Lynnfield
may be just what the doctor ordered. From a pure performance/price standpoint,
the i5-750 represents a solid value, giving stiff competition to the
similarly priced, but higher-clocked Intel Q9550 and AMD X4
955 BE. The i7-870 on the other hand is LGA1156's flagship, and as such,
is tagged with a heavy price premium. In most cases, the kind of money
the i7-870 commands is better spent on a cheaper CPU with the savings distributed
to other system components such as graphics cards and solid state drives.
CPU pricing is not the only thing to consider in regards to value — motherboards
and memory are the other main factors. Solid information about LGA1156 motherboards
is hard to come by with most rumors/speculation indicating a $100 price-point
at the low-end, and upwards of $300 at the high-end. The street price for memory
still favors DDR2 — 4GB of DDR3-1333 goes for $20 more than DDR2-800. Penny-pinchers
may consider an AM3 quad core paired with a AM2+ motherboard a more palatable
choice, especially if they've already invested in DDR2. A DDR2 powered Core
2 Quad system is somewhat less viable, given that LGA775 is nearing its end. In summary, LGA1156 looks like a natural and positive transition forward from 775.
Our thanks to Intel
and Thermalright
for the product samples used in this review.
* * *
Articles of Related Interest
AMD's
785G Chipset Boards: 780G Evolved
Intel Q9550S: A Greener Quad Core?
AMD Phenom II X2 550 BE & Athlon
II X2 250
AMD Phenom II X4 955 Black Edition for
AM3
Phenom II: AMD pulls closer
Intel Core i7: Nehalem Launched
* * *
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