The prospects of deploying Optical Burst Switching (OBS) in next generation all-optical transport networks would greatly benefit, in terms of ease of implementation and cost, from reducing or even avoiding the use of wavelength converters at the network nodes. This paper presents a performance evaluation of strategies to minimize wavelength contention in OBS networks by optimizing the wavelength assignment at the bursts ingress nodes. The wavelength contention minimization strategy recently proposed by the authors is shown to outperform a previously proposed strategy, in some cases by several orders of magnitude in terms of average burst blocking probability. A tighter performance bound for these strategies is devised. Moreover, the network conditions that enhance the effectiveness of using these strategies in OBS networks without wavelength converters are also discussed.