With advances in process technology, soft errors(SE)are becoming an increasingly critical design concern. Due to their large area and high density, caches are worst hit by soft errors. Although Error Correction Code based mechanisms protect the data in caches, they have high performance and power overheads. Since multimedia applications are increasingly being used in mission-critical embedded systems where both reliability and energy are a major concern, there is a de?nite need to improve reliability in embedded systems, without too much energy overhead. We observe that while a soft error in multimedia data may only result in a minor loss in QoS, a soft error in avariable that controls the execution ?ow of the program may be fatal. Consequently, we propose to partition the data space into failure critical and failure non-critical data, and provide a high-degree of soft error protection only to the failure critical data in Horizontally Partitioned Caches. Experimental results demonstrate that our selective data protection can achieve the failure rate close to that of a soft error protected cache system, while retaining the performance and energy consumption similar to those of a traditional cache system, with some degradation in QoS. For example, for conventional con?guration as in IntelXScale, our approach achieves the same failure rate, while improving performance by 28% and reducing energy consumption by 29%in comparison with a soft error protected cache.