The most awaited processor line-up of this year is finally out.
Last time we saw so much hype around an Intel processor was when the six-core performance powerhouse Gulftown- Intel Core i7-980X was launched. Gulftown is still the fastest desktop processor on the planet, despite AMD coming out with its Thuban series of hex-core processors.
Sandy Bridge was announced in September 2010 at Intel Developer Forum in San Francisco and managed to vow most of us with its plethora of features including a graphics processor on the same die as the cores. Sandy Bridge being a new microarchitecture follows the 'tock' in Intel's 'tick-tock' cycle of shrinking process and new microarchitechture model.
Sandy Bridge is based on Intel's high speed 32-nm fabrication process and is the second generation of the Core i3/i5/i7 processors. Naming convention will be similar to the Core i3/i5/i7 series processors except that for Sandy Bridge based processors, the prefix 2 (indicating second generation) will be followed by the SKU. For instance, the two processors that we will see in the following pages are Intel Core i7-2600K and Intel Core i5- 2500K. Suffixes like K, S, T and M will be seen in some processor based on their purpose. For instance K indicates processor with unlocked cores, M indicates mobile processors for notebooks and so on.
This line of processors will need a completely new socket – LGA 1155. These processors are not backward compatible on the earlier LGA 1156 sockets even though the size of the socket is the same. However, you can still use the cooler on your LGA 1156 socket on the new motherboards. At present, there are two chipsets namely Intel P67 and Intel H67 on which majority of the motherboards are based. Let’s have a look at the processors on offer. We will only be looking at desktop processors for now and talking about Core i7-2600K and Core i5-2500K processors in the test.
This line up contains processors meant for the enthusiasts, with the i7-2600K and i5-2500K coming with unlocked multipliers.
This is the lower end models. Note that Core i3 processors support hyper threading but not Turbo Boost.
Finally we have the low power, entry level line of Sandy Bridge processors meant for the HTPC crowd and for users who want a comparatively lower power system.
We got two Sandy Bridge processors in our Test Centre namely Intel Core i7-2600K and Intel Core i5-2500K. So before we get to the benchmarks, I would like to give you a brief overview of the new features that are present in this new microarchitecture.
The New Microarchitecture
As seen in the diagram above, Sandy Bridge microarchitechture is all about integration. What was formerly seen on North Bridge chipsets in Intel motherboards, has all come on the processor die itself. Even the integrated graphics, which were found inside the Clarkdale processor but on a different die from the core die, have moved in alongside the Sandy Bridge processor cores. The modular arrangement comprises of five main sections namely the quad cores, processor graphics, System Agent (which is basically a North Bridge with a new name as it contains PCI Express, DDR, power controllers and the DMI interface) and the shared L3 cache also known as the Last Level Cache (LLC). Due to closer integration, the base clock frequency has come down from 133MHz to 100MHz, and this frequency clock is used for all the internal components.
All the Core i7 processors will feature both Hyper threading as well as Turbo Boost whereas Core i5 line will have only Turbo Boost and finally Core i3 processors will have only Hyper threading.
In short :
Core i7 – 4 Cores / 8 Threads with Turbo Boost – 4C/8T w TB
Core i5 – 4C / 4T w TB
Core i3 – 2C / 4T w/o TB
Integrated Graphics
Sandy Bridge's crowning glory is the implementation of graphics on the same 32-nm die as the processor. The two processors we got ie. Core i7-2600K and Core i5-2500K had Intel HD 3000 integrated graphics (IG) whereas the other lower end models like Core i3-2100 has the Intel HD 2000.
When compared to the previous generation integrated graphics solutions, the number of execution units hasn't increased - 12 for HD 3000 and 6 for HD 2000. The new IG has support for DirectX 10.1, Open GL 3.0, and is capable of playing 3D stereoscopic Blu-Ray content as it has an HDMI v1.4a support which wasn't present in the earlier generation IG.
The IG on Sandy Bridge implements a technology similar to Turbo Boost, allowing the maximum GPU speed to hit 1350MHz, a whopping 450MHz jump from the maximum speed found on the previous generation IG solutions.
While HD 3000 is present on the K series processors with the unlocked core that we got, the graphics cannot be utilised at all on a P67 based motherboard. You will have to use an H67 based motherboard, which only allows graphics overclocking, to make use of the integrated graphics of the Sandy Bridge processor. We will touch upon this in detail in the 'Quick Sync Video' page.
Advanced Vector Extensions – AVX
AVX is a new extension set which is capable of handling 256-bit Floating Point executions which is twice the jump from today's 128-bit Floating Point Units. This bodes well for all your floating point intensive applications like 3D modelling, scientific simulation software, audio and video processing which involve heavy mathematical operations. But you can only make use of AVX if your software is compatible with it. Using Windows 7 Service Pack 1, you can enable it at the OS level.
Turbo Boost V2.0
Intel's Turbo Boost dynamically raises the frequency of active cores beyond the stock speeds so long as the processor is operating within the thermal design power (TDP). In Sandy Bridge, this feature has been tweaked a bit to give more thermal headroom while boosting up the frequencies. What this essentially means is that the boost can operate beyond the TDP limitations for a short period of time till the processor heats up to the maximum limit, which is when the clock frequency drops such that the TDP limit is maintained. Although this is a nice feature, in real life testing it does not drastically improve the performance.
Another interesting aspect is that boosting of frequencies on the processor as well as graphic cores can be determined by the nature of the task. According to Intel in a 3D heavy task the power control unit may favour the graphics core more than CPU cores as that will tend to get the work done faster.
Limited Overclocking
In Sandy Bridge processors, you can only overclock by adjusting the multiplier ie. Overclockers should only look at K series processors. This may come as a rude shock to enthusiasts, who previously would also overclock a processor with a locked multiplier by playing with the Base Clock frequency (BCLK). Now thanks to the integration of all the controllers like USB, SATA, power controllers, graphics unit onto the same die as the cores, BCLK is set to 100 MHz for all blocks. So if you change the BCLK from 100MHz, it may mess up other controllers. Also H67 based motherboards will allow only graphics overclocking.
Ring Bus Architechture
Intel has implemented a ring bus architechture which helps communicate between the processor cores, processor graphics, system agent and last level cache. The ring basically comprises of the 32-byte data ring, a request ring, an acknowledgment ring and a snoop ring. The ring is pipelined and runs at the same frequency and voltage as the other components on the die. This helps to speed up the communication between processor core, graphics and system agent. Also as the last level cache is common to all, as you increase the number of cores, the number of stops on the ring bus will scale up accordingly.
SOURCE : THINKDIGIT
Last time we saw so much hype around an Intel processor was when the six-core performance powerhouse Gulftown- Intel Core i7-980X was launched. Gulftown is still the fastest desktop processor on the planet, despite AMD coming out with its Thuban series of hex-core processors.
Sandy Bridge was announced in September 2010 at Intel Developer Forum in San Francisco and managed to vow most of us with its plethora of features including a graphics processor on the same die as the cores. Sandy Bridge being a new microarchitecture follows the 'tock' in Intel's 'tick-tock' cycle of shrinking process and new microarchitechture model.
Sandy Bridge is based on Intel's high speed 32-nm fabrication process and is the second generation of the Core i3/i5/i7 processors. Naming convention will be similar to the Core i3/i5/i7 series processors except that for Sandy Bridge based processors, the prefix 2 (indicating second generation) will be followed by the SKU. For instance, the two processors that we will see in the following pages are Intel Core i7-2600K and Intel Core i5- 2500K. Suffixes like K, S, T and M will be seen in some processor based on their purpose. For instance K indicates processor with unlocked cores, M indicates mobile processors for notebooks and so on.
This line of processors will need a completely new socket – LGA 1155. These processors are not backward compatible on the earlier LGA 1156 sockets even though the size of the socket is the same. However, you can still use the cooler on your LGA 1156 socket on the new motherboards. At present, there are two chipsets namely Intel P67 and Intel H67 on which majority of the motherboards are based. Let’s have a look at the processors on offer. We will only be looking at desktop processors for now and talking about Core i7-2600K and Core i5-2500K processors in the test.
This line up contains processors meant for the enthusiasts, with the i7-2600K and i5-2500K coming with unlocked multipliers.
This is the lower end models. Note that Core i3 processors support hyper threading but not Turbo Boost.
Finally we have the low power, entry level line of Sandy Bridge processors meant for the HTPC crowd and for users who want a comparatively lower power system.
We got two Sandy Bridge processors in our Test Centre namely Intel Core i7-2600K and Intel Core i5-2500K. So before we get to the benchmarks, I would like to give you a brief overview of the new features that are present in this new microarchitecture.
The New Microarchitecture
As seen in the diagram above, Sandy Bridge microarchitechture is all about integration. What was formerly seen on North Bridge chipsets in Intel motherboards, has all come on the processor die itself. Even the integrated graphics, which were found inside the Clarkdale processor but on a different die from the core die, have moved in alongside the Sandy Bridge processor cores. The modular arrangement comprises of five main sections namely the quad cores, processor graphics, System Agent (which is basically a North Bridge with a new name as it contains PCI Express, DDR, power controllers and the DMI interface) and the shared L3 cache also known as the Last Level Cache (LLC). Due to closer integration, the base clock frequency has come down from 133MHz to 100MHz, and this frequency clock is used for all the internal components.
All the Core i7 processors will feature both Hyper threading as well as Turbo Boost whereas Core i5 line will have only Turbo Boost and finally Core i3 processors will have only Hyper threading.
In short :
Core i7 – 4 Cores / 8 Threads with Turbo Boost – 4C/8T w TB
Core i5 – 4C / 4T w TB
Core i3 – 2C / 4T w/o TB
Integrated Graphics
Sandy Bridge's crowning glory is the implementation of graphics on the same 32-nm die as the processor. The two processors we got ie. Core i7-2600K and Core i5-2500K had Intel HD 3000 integrated graphics (IG) whereas the other lower end models like Core i3-2100 has the Intel HD 2000.
When compared to the previous generation integrated graphics solutions, the number of execution units hasn't increased - 12 for HD 3000 and 6 for HD 2000. The new IG has support for DirectX 10.1, Open GL 3.0, and is capable of playing 3D stereoscopic Blu-Ray content as it has an HDMI v1.4a support which wasn't present in the earlier generation IG.
The IG on Sandy Bridge implements a technology similar to Turbo Boost, allowing the maximum GPU speed to hit 1350MHz, a whopping 450MHz jump from the maximum speed found on the previous generation IG solutions.
While HD 3000 is present on the K series processors with the unlocked core that we got, the graphics cannot be utilised at all on a P67 based motherboard. You will have to use an H67 based motherboard, which only allows graphics overclocking, to make use of the integrated graphics of the Sandy Bridge processor. We will touch upon this in detail in the 'Quick Sync Video' page.
Advanced Vector Extensions – AVX
AVX is a new extension set which is capable of handling 256-bit Floating Point executions which is twice the jump from today's 128-bit Floating Point Units. This bodes well for all your floating point intensive applications like 3D modelling, scientific simulation software, audio and video processing which involve heavy mathematical operations. But you can only make use of AVX if your software is compatible with it. Using Windows 7 Service Pack 1, you can enable it at the OS level.
Turbo Boost V2.0
Intel's Turbo Boost dynamically raises the frequency of active cores beyond the stock speeds so long as the processor is operating within the thermal design power (TDP). In Sandy Bridge, this feature has been tweaked a bit to give more thermal headroom while boosting up the frequencies. What this essentially means is that the boost can operate beyond the TDP limitations for a short period of time till the processor heats up to the maximum limit, which is when the clock frequency drops such that the TDP limit is maintained. Although this is a nice feature, in real life testing it does not drastically improve the performance.
Another interesting aspect is that boosting of frequencies on the processor as well as graphic cores can be determined by the nature of the task. According to Intel in a 3D heavy task the power control unit may favour the graphics core more than CPU cores as that will tend to get the work done faster.
Limited Overclocking
In Sandy Bridge processors, you can only overclock by adjusting the multiplier ie. Overclockers should only look at K series processors. This may come as a rude shock to enthusiasts, who previously would also overclock a processor with a locked multiplier by playing with the Base Clock frequency (BCLK). Now thanks to the integration of all the controllers like USB, SATA, power controllers, graphics unit onto the same die as the cores, BCLK is set to 100 MHz for all blocks. So if you change the BCLK from 100MHz, it may mess up other controllers. Also H67 based motherboards will allow only graphics overclocking.
Ring Bus Architechture
Intel has implemented a ring bus architechture which helps communicate between the processor cores, processor graphics, system agent and last level cache. The ring basically comprises of the 32-byte data ring, a request ring, an acknowledgment ring and a snoop ring. The ring is pipelined and runs at the same frequency and voltage as the other components on the die. This helps to speed up the communication between processor core, graphics and system agent. Also as the last level cache is common to all, as you increase the number of cores, the number of stops on the ring bus will scale up accordingly.
SOURCE : THINKDIGIT